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Enaliosuchus macrospondylus Koken, 1883 was one of the first thalattosuchian taxa from the Cretaceous to be described. The type series includes an atlas-axis complex, remnants of three post-axial cervical vertebrae, several dorsal vertebrae, a caudal vertebra, an incomplete femur and a fragmentary sacral rib from the upper Valanginian of northern Germany. Additionally, two isolated, non-thalattosuchian, tooth crowns from the uppermost Valanginian to lowermost Hauterivian of different localities in northern Germany were tentatively assigned to E. macrospondylus by Koken. The taxon was established for the distinctive the atlas-axis morphology, in particular the apparent lack of an axis parapophysis. Enaliosuchus macrospondylus has been considered a valid taxon in recent studies, based upon a largely complete metriorhynchid specimen from the Valanginian of France that had been referred to this taxon, an assignment that has never been questioned. Here we provide a detailed re-description of the E. macrospondylus holotype specimen and determine whether it is diagnostic, and if a referral of the French specimen to E. macrospondylus is justified. We also discuss whether E. macrospondylus and another metriorhynchid specimen from the Valanginian of northern Germany, described as Enaliosuchus schroederi, are conspecific. Finally, we provide an overview of the current knowledge of metriorhynchid diversity during the Cretaceous.

Isolated remains of mosasaurids and plesiosaurians are recorded from the lower Campanian Bottrop and Vaals formations of North Rhine-Westphalia, western Germany. A tooth crown from Bottrop-Fuhlenbrock, referred to an elasmosaurid plesiosaurian, represents the first record of this group from late-Upper Cretaceous strata of the area. Another presumed plesiosaurian remain is a fragmentary gastralium from Duisburg-Walsum. Some of the mosasaurid material from the Bottrop Formation (a tooth crown and a vertebra from Duisburg-Walsum and Bottrop-Fuhlenbrock) is assigned to the subfamily Plioplatecarpinae. The Vaals Formation, which is a lateral equivalent of the Bottrop Formation, yielded a single tooth crown, found at Aachen-Bildchen, that is here referred to the genus Hainosaurus . These finds from the Bottrop and Vaals formations constitute evidence for the presence of mosasaurids and plesiosaurians in proximal shelf to nearshore settings during the Campanian. The mosasaurid occurrences in particular may be an indicator that diversity and abundance increased in more basinward facies and a greater palaeowaterdepth.

Hornung, J.J., Reich, M. & Frerichs, U., February 2018. The mosasaur fauna (Squamata: Mosasauridae) from the Campanian (Upper Cretaceous) of Hannover, northern Germany. Alcheringa 42, 543-559. ISSN...

Sachs, S., Hornung, J.J., Lallensack, J.N. & Kear, B.P., November.2017. First evidence of a large predatory plesiosaurian from the Lower Cretaceous non-marine ‘Wealden facies’ deposits of northwestern Germany. Alcheringa 42, 501-508. ISSN 0311-5518.Here, we describe the incomplete mandible of a large-skulled ‘pliosauromorph’ plesiosaurian from the Lower Cretaceous (Berriasian) of northwestern Germany. The fossil derives from limnic–brackish ‘Wealden facies’ deposits of the Deister Formation (Buckeberg Group), and is preserved as a natural mould in fine-grained sandstone. Examination of the original remains, in conjunction with a three-dimensional photogrammetrically digitized ‘cast’, revealed a conspicuous rosette of symphyseal alveoli, which would otherwise typically characterize Early–Middle Jurassic macrophagous plesiosaurians including rhomaleosaurids and the pliosaurid Simolestes. The Deister Formation ‘pliosauromorph’ represents the first record of a large-bodied plesiosaurian macrocarnivore from th...

An isolated hyomandibula from a lower Toarcian carbonate concretion of the Ahrensburg erratics assemblage (Schleswig-Holstein, northern Germany) represents the first record of a chondrosteid fish from the Lower Jurassic of the southwestern Baltic realm. Except for its smaller size, the specimen is morphologically indistinguishable from corresponding elements ofGyrosteus mirabilisfrom the Toarcian of Yorkshire, England. This find, which probably originates from the western Baltic basin between Bornholm Island (Denmark) and northeastern Germany, markedly expands the known range of this chondrosteid taxon across the northern part of the strait connecting the Boreal Sea with the Tethys Ocean during the Early Jurassic. For the first time the extension of the paleogeographic range of a chondrosteid species beyond its type area is documented, which can contribute to future studies of vertebrate faunal provincialism during the Lower Jurassic in Europe.

Two genera of tylosaurine mosasaurs, Tylosaurus and Hainosaurus, are recorded for the first time from Germany. Tylosaurus sp. is represented by two isolated tooth crowns, originally described as Mosasaurus? alseni (here considered a nomen dubium) from the latest Santonian–Early Campanian, which are very similar to T. ivoensis and T. gaudryi. The material of Hainosaurus sp. comprises a maxillary with associated postorbitofrontal, two pterygoid teeth and several indeterminate cranial fragments. The specimen from the Late Campanian is slightly less derived than H. bernardi from the Maastrichtian in retaining labiolingually less compressed anterior maxillary teeth and unserrated pterygoid teeth with only very weak carinae. Despite only minor skeletal differences, the genus Hainosaurus is considered to be distinct from Tylosaurus because of its significant modification of the dental apparatus compared to the plesiomorphic condition in the latter. This dental morphology suggests a phylogenetic trend from a generalised-piercing marginal dentition in Tylosaurus towards the increasingly labiolingually compressed, symmetrical, strongly bicarinate cutting marginal teeth in Hainosaurus spp. from the Early through Late Campanian and Maastrichtian. A similar trend is also present in pterygoid teeth with very indistinct unserrated carinae in the Campanian Hainosaurus sp. towards serrated ones in the Maastrichtian H. bernardi. A short review indicates the presence of Hainosaurus in northern, central and western Europe (Sweden to Spain) since the Early Campanian, and the occurrence of Tylosaurus spp. in the same area until the Late Campanian. Hainosaurus persisted until the end of the Maastrichtian; outside Europe it may have been present in the Late Campanian of the USA and the Maastrichtian of the Democratic Republic of Congo. Judging from a simple, uni- to bicarinate, stoutly conical tooth morphology in aigialosaurs and very basal mosasaurs as well as phylogenetic patterns, the development of blade-like cutting tooth crowns appears to have been convergent in several clades of large-bodied Campanian–Maastrichtian mosasaurids. These include both mosasaurines ('Leiodon' mosasauroides, Prognathodon? sectorius, Prognathodon? kianda, Eremiasaurus heterodontus) and tylosaurines (Hainosaurus spp.).

In Germany, mosasaur remains are very rare and only incompletely known. However, the earliest records date back to the 1830s, when tooth crowns were found in the chalk of the Isle of Rügen. A number of prominent figures in German palaeontology and geosciences of the 19th and 20th centuries focused on these remains, including, among others, Friedrich von Hagenow, Hermann von Meyer, Andreas Wagner, Hanns Bruno Geinitz and Josef Pompeckj. Most of these works were only short notes, given the scant material. However, the discovery of fragmentary cranial remains in Westphalia in 1908 led to a more comprehensive discussion, which is also of historical importance, as it illustrates the discussions on the highly controversial and radical universal phylogenetic theory proposed by Gustav Steinmann in 1908. This theory saw the existence of continuous lines of descent, evolving in parallel, and did not regard higher taxonomic units as monophyletic groups but as intermediate paraphyletic stages of evolution. In this idea, nearly all fossil taxa form part of these lineages, which extend into the present time, and natural extinction occurs very rarely, if ever. In Steinmann's concept, mosasaurs were not closely related to squamates but formed an intermediate member in a anagenetic chain from Triassic thalattosaurs to extant baleen whales. The newly found specimen led Josef Pompeckj to write a vehement rebuttal to Steinmann's theory, published in 1910, showing that his conclusions were conjectural and speculative, being based on convergence and not supported by scientific evidence. This particular specimen, housed in Göttingen, later also inspired a piece of palaeoart by Franz Roubal under the instructions of Othenio Abel.With the exception of a vertebra from the Campanian of former East Prussia (now Russian Federation), and a possible vertebra from the Cenomanian of Dresden, Saxony, all datable material – today partly lost – originated from the northern part of present-day Germany and stratigraphically from the Campanian–Maastrichtian. The purported record from the Cenomanian of Bavaria (southeastern Germany) was most probably an error, based on Upper Jurassic crocodilian material.

Metatetrapous valdensis Nopcsa, 1923 from the late Berriasian of northwestern Germany was the first dinosaur ichnotaxon ever attributed to a thyreophoran trackmaker. However, the subsequent lost of the original material made this identification and the status of the ichnotaxon questionable for many subsequent authors. This situation was aggravated by the fact that there are only very brief original descriptions accompanied by a single drawing. A reconsideration of the original description recognizes M. valdensis as a valid ichnotaxon, which, albeit showing great resemblance in pes morphology to similar ichnotaxa, stands out from them by a tetradactyl manus. It not only holds its original systematic attribution, but also has sparked early hypotheses on the phylogeny of dinosaurs already in 1922, possibly for the first time based upon tracks. Two surviving natural hypichnial casts of ankylosaurian pes imprints from the same stratum cannot be straightforwardly identified with the type material due to a lack ...

A well-preserved isolated manus impression evidences the presence of derived aquatic adaptations in the forelimb morphology of Berriasian turtles. Size and the abundant co-occurring turtle fauna indicate that the track was left by a large-sized, bottom-walking basal pancryptodiran. The footprint shows an interesting mosaic of primitive and derived features. The basic turtle pattern is reflected by a short and broad autopodium but thin phalanges, claw reduction and extensive webbing enclosing the digits and lateral and medial margins of the distal metapodium are clearly specialized features related to the aquatic environment. Some characters including the proportional elongation of the first digit, which reached as far distally as the other digits and was probably highly mobile at the metacarpal-phalangeal joint, indicate an even higher degree of specialization. The specimen gives evidence on a hitherto unknown range of appendicular modification in Early Cretaceous turtles, and redundantly proves the aquatic habitat and locomotion of large-sized turtles from the Berriasian of northwestern Germany.

Two genus-group names of flat-worms— Leptocleidus Mueller, 1936 and Macrorhynchus von Graff, 1882—are junior homonyms that are preoccupied by fossil diapsid reptile genera— Leptocleidus Andrews, 1922, and Macrorhynchus Dunker, 1843—and an extant teleost fish genus— Macrorhynchus [Gmelin, 1801] ex La Cepede, 1800. These are replaced by nomina nova ( Pharyngodytes nom. nov.; Graffiellus nom. nov.). Macrorhynchus [Gmelin, 1801] is an objective senior synonym of Macrorhyncus Dumeril, 1805 ex La Cepede, 1800 (syn. nov.), and a senior homonym of Macrorhynchus Dunker, 1843, and Macrorhynchus von Graff, 1882.

The periorbital morphology of goniopholidids is discussed, exploring the diversity of patterns and the relevance of the data for phylogenetic studies. Revision of material is focused on Goniopholis spp. and aff. Goniopholis spp., from England, Germany, and Belgium, providing a comparative description of their interorbital morphology. Traditional interpretation of the interorbital elements in species of Goniopholis (G. simus, G. baryglyphaeus), where the frontal is interpreted as excluded from the orbit by a prefrontal-postorbital contact in the skull roof, is contested and clarified through the analysis of new specimens, including a morphometric analysis. In Goniopholis, failure to identify the palpebral and its subtle contact with the prefrontal has lead to misinterpretation of elements and structures near the orbit, and the differential preservation/loss of palpebrals explains variability of the orbit in shape and orientation. In all European goniophilidids the frontal reaches the primary orbit...

The holotype ofBrancasaurus brancaiis one of the most historically famous and anatomically complete Early Cretaceous plesiosaurian fossils. It derived from the Gerdemann & Co. brickworks clay pit near Gronau (Westfalen) in North Rhine-Westphalia, northwestern Germany. Stratigraphically this locality formed part of the classic European “Wealden facies,” but is now more formally attributed to the upper-most strata of the Bückeberg Group (upper Berriasian). Since its initial description in 1914, the type skeleton ofB. brancaihas suffered damage both during, and after WWII. Sadly, these mishaps have resulted in the loss of substantial information, in particular many structures of the cranium and limb girdles, which are today only evidenced from published text and/or illustrations. This non-confirmable data has, however, proven crucial for determining the relationships ofB. brancaiwithin Plesiosauria: either as an early long-necked elasmosaurid, or a member of the controversial Early Cretaceous leptocleidid radiation. To evaluate these competing hypotheses and compile an updated osteological compendium, we undertook a comprehensive examination of the holotype as it is now preserved, and also assessed other Bückeberg Group plesiosaurian fossils to establish a morphological hypodigm. Phylogenetic simulations using the most species-rich datasets of Early Cretaceous plesiosaurians incorporating revised scores forB. brancai, together with a second recently named Bückeberg Group plesiosaurianGronausaurus wegneri(Hampe, 2013), demonstrated that referral of these taxa to Leptocleididae was not unanimous, and that the topological stability of this clade is tenuous. In addition, the trait combinations manifested byB. brancaiandG. wegneriwere virtually identical. We therefore conclude that these monotypic individuals are ontogenetic morphs andG. wegneriis a junior synonym ofB. brancai. Finally, anomalies detected in the diagnostic features for other “Wealden” plesiosaurians have prompted reconsiderations of interspecies homology versus intraspecific variability. We therefore propose that the still unresolved taxonomy ofB. brancaishould emphasize only those character states evident in the examinable fossil material, and specifically accommodate for growth-related modifications delimited via osteologically mature referred specimens.

The fragmentary remains of a juvenile rhabdodontid ornithopod from the Coal-bearing Complex of the Gosau Group (Lower Campanian, Grunbach syncline) at Muthmannsdorf near Wiener Neustadt, Lower Austria are revised. The material, probably belonging to a single individual, includes a right dentary (lectotype of Iguanodon suessi Bunzel, 1871, designated herein), teeth, a fragmentary parietal, fragments of scapula, ?radius, femur, tibia, two vertebrae (lost) and a manual ungual. The lectotype dentary does not provide clear autapomorphies or sufficient diagnostic features to determine its position within the Rhabdodontidae at generic level. By this “Iguanodon suessi” Bunzel, 1871 and the genus “Mochlodon” Seeley, 1881, to which it was latter referred as type species, cannot be characterized sufficiently by differential diagnosis and these are best considered nomina dubia. Based upon combined character comparisons (mainly postcranial features) the Muthmannsdorf ornithopod is referred herein to Zalmoxes Weishampel, Jianu, Csiki and Norman, 2003, a genus so far known from the late Maastrichtian of Romania. It probably but not evidently represents a yet unnamed species, most closely related to Zalmoxes shqiperorum Weishampel, Jianu, Csiki and Norman, 2003. At the present state of knowledge the Austrian material is not further diagnostic at the species level and kept in open nomenclature as Zalmoxes sp.

Here we report on a new basal elasmosaurid plesiosaurian, Lagenanectes richterae, gen. et sp. nov., from the Lower Cretaceous (probably Upper Hauterivian) of Germany. The material includes a partia...

A fragmentary cervico-pectoral lateral spine and partial humerus of an ankylosaur from the Early Cretaceous (early Valanginian) of Gronau in Westfalen, northwestern Germany, are described. The spine shows closest morphological similarities to the characteristic cervical and pectoral spines of Hylaeosaurus armatus from the late Valanginian of England. An extensive comparison of distal humeri among thyreophoran dinosaurs supports systematic differences in the morphology of the distal condyli between Ankylosauria and Stegosauria and a referral of the Gronau specimen to the former. The humerus fragment indicates a rather small individual, probably in the size range of H. armatus, and both specimens are determined herein as ?Hylaeosaurus sp.. A short overview of other purported ankylosaur material from the Berriasian-Valanginian of northwest Germany shows that, aside from the material described herein, only tracks can be attributed to this clade with confidence at present. peerReviewed

BackgroundArchosaurs (birds, crocodilians and their extinct relatives including dinosaurs) dominated Mesozoic continental ecosystems from the Late Triassic onwards, and still form a major component of modern ecosystems (>10,000 species). The earliest diverse archosaur faunal assemblages are known from the Middle Triassic (c. 244 Ma), implying that the archosaur radiation began in the Early Triassic (252.3-247.2 Ma). Understanding of this radiation is currently limited by the poor early fossil record of the group in terms of skeletal remains.Methodology/principal findingsWe redescribe the anatomy and stratigraphic position of the type specimen of Ctenosauriscus koeneni (Huene), a sail-backed reptile from the Early Triassic (late Olenekian) Solling Formation of northern Germany that potentially represents the oldest known archosaur. We critically discuss previous biomechanical work on the 'sail' of Ctenosauriscus, which is formed by a series of elongated neural spines. In addition, we describe Ctenosauriscus-like postcranial material from the earliest Middle Triassic (early Anisian) Röt Formation of Waldhaus, southwestern Germany. Finally, we review the spatial and temporal distribution of the earliest archosaur fossils and their implications for understanding the dynamics of the archosaur radiation.Conclusions/significanceComprehensive numerical phylogenetic analyses demonstrate that both Ctenosauriscus and the Waldhaus taxon are members of a monophyletic grouping of poposauroid archosaurs, Ctenosauriscidae, characterised by greatly elongated neural spines in the posterior cervical to anterior caudal vertebrae. The earliest archosaurs, including Ctenosauriscus, appear in the body fossil record just prior to the Olenekian/Anisian boundary (c. 248 Ma), less than 5 million years after the Permian-Triassic mass extinction. These earliest archosaur assemblages are dominated by ctenosauriscids, which were broadly distributed across northern Pangea and which appear to have been the first global radiation of archosaurs.

Few identification methods will rapidly or specifically detect all bacteria in the order Chlamydiales , family Chlamydiaceae . In this study, three PCR tests based on sequence data from over 48 chlamydial strains were developed for identification of these bacteria. Two tests exclusively recognized the Chlamydiaceae : a multiplex test targeting the ompA gene and the rRNA intergenic spacer and a TaqMan test targeting the 23S ribosomal DNA. The multiplex test was able to detect as few as 200 inclusion-forming units (IFU), while the TaqMan test could detect 2 IFU. The amplicons produced in these tests ranged from 132 to 320 bp in length. The third test, targeting the 23S rRNA gene, produced a 600-bp amplicon from strains belonging to several families in the order Chlamydiales . Direct sequence analysis of this amplicon has facilitated the identification of new chlamydial strains. These three tests permit ready identification of chlamydiae for diagnostic and epidemiologic study. The specificity of these tests indicates that they might also be used to identify chlamydiae without culture or isolation.

In contrast to mouse epidermal cells, human skin keratinocytes are rather resistant to transformation in vitro. Immortalization has been achieved by SV40 but has resulted in cell lines with altered differentiation. We have established a spontaneously transformed human epithelial cell line from adult skin, which maintains full epidermal differentiation capacity. This HaCaT cell line is obviously immortal (greater than 140 passages), has a transformed phenotype in vitro (clonogenic on plastic and in agar) but remains nontumorigenic. Despite the altered and unlimited growth potential, HaCaT cells, similar to normal keratinocytes, reform an orderly structured and differentiated epidermal tissue when transplanted onto nude mice. Differentiation-specific keratins (Nos. 1 and 10) and other markers (involucrin and filaggrin) are expressed and regularly located. Thus, HaCaT is the first permanent epithelial cell line from adult human skin that exhibits normal differentiation and provides a promising tool for studying regulation of keratinization in human cells. On karyotyping this line is aneuploid (initially hypodiploid) with unique stable marker chromosomes indicating monoclonal origin. The identity of the HaCaT line with the tissue of origin was proven by DNA fingerprinting using hypervariable minisatellite probes. This is the first demonstration that the DNA fingerprint pattern is unaffected by long-term cultivation, transformation, and multiple chromosomal alterations, thereby offering a unique possibility for unequivocal identification of human cell lines. The characteristics of the HaCaT cell line clearly document that spontaneous transformation of human adult keratinocytes can occur in vitro and is associated with sequential chromosomal alterations, though not obligatorily linked to major defects in differentiation.

Involucrin, the major protein precursor of the cornified envelope, is expressed during terminal differentiation of human keratinocytes, both in vivo and in vitro. In epidermis, the onset of synthesis is several layers above the basal layer, but in stratified cultures of keratinocytes on tissue culture plastic involucrin synthesis begins in the first suprabasal layer. To investigate the reason for this premature expression, the distribution of involucrin was studied in epidermis from different body sites, in organotypic cultures and in transplants of keratinocytes onto nude mice. We found that premature expression was not associated with poor morphological differentiation, because involucrin synthesis began immediately above the basal layer even when distinct basal, spinous, granular and cornified layers were formed in organotypic cultures recombined with dermis. The site of involucrin expression in culture did not depend on the number of cornified layers present. The only conditions which resulted in an upward shift in the site of synthesis were in 3-week old transplants on nude mice. We conclude that the site of onset of involucrin synthesis is not determined by the degree of morphological differentiation of the tissue, and discuss other factors which may be involved.

1. 1. Radioimmunochromatographic analysis of adrenal incubates is a useful method for the characterization of uncommon and unidentified steroid fractions. In incubates of normal adrenals at least seven uncommon fractions were separated. 2. 2. Uncommon and unidentified steroids may react also with antibodies of apparently high specificity. This observation may have practical consequences for in vivo studies. 3. 3. Under pathophysiological conditions such as adrenal regeneration hypertension steroids may be produced by adrenocortical tissue which are not detectable in incubates of normal adrenals.

Six malignant C3H mouse epidermal cell lines (HEL-30, HEL-37, HELP I, HELP IV, HD II, H3L), with different capacities for epidermal differentiation, were analyzed for their organized growth behavior and basement membrane (BM) formation in organotypical cultures in vitro and after transplantation into syngeneic mice. Expression and deposition of five BM components (type IV collagen, laminin, bullous pemphigoid antigen, fibronectin, heparan sulfate proteoglycan) were determined on frozen sections by indirect immunofluorescence. Additionally, synthesis and secretion of BM components by the line HEL-30 (in submersed cultures) were identified by metabolic labeling and immunoprecipitation. Morphologic differentiation features and formation of a structured BM were studied by electron microscopy. All cell lines were tumorigenic and invasive but nevertheless able to synthesize BM constituents in vitro and in vivo, although pronounced variations in the expression and the polarity and continuity of deposition were found. Irrespective of the amount of BM components synthesized, none of the cell lines formed a structured BM in organotypical cultures in vitro. After transplantation the production of BM components was improved and the newly formed epithelia were separated from the mesenchyme by a structured BM. The formation of BM occurred whether the epithelial cells were in immediate contact with the mesenchyme or separated by a 1 to 2 mm thick native collagen gel. Deposition of BM constituents and formation of BM structures occurred both at the superficial epithelium and around invading cell cords. The studies clearly demonstrated that malignant epidermal cells maintain their capacity to synthesize BM components. The extent of production and the polarity of deposition of the constituents and the quality of BM formation were usually higher in well differentiated cell lines and obviously correlated well with their preserved degree of differentiation. Comparable to normal keratinocytes, formation of structured BM requires interaction with living mesenchyme but occurs independently of direct epidermal-mesenchymal contact.

The northern German Lower Cretaceous Bückeberg Formation yields numerous dinosaur tracksites, some of which have produced material of impressive quality. Stratigraphically, the localities are concentrated in the Obernkirchen Sandstone, a thin subunit within this formation. The Obernkirchen Sandstone represents mainly a sandy barrier to back-barrier and lagoonal setting within a limnic deltaic facies complex, which was deposited during the late Berriasian (Cypridea alta formosa ostracod subzone) in the southeast of the Lower Saxony Basin, northwest Germany. A few tracksites occur more proximally in coeval fluvial deposits. Dinosaur footprint assemblages were left by ornithopods, theropods, sauropods, ankylosaurs, and small, bipedal ornithischians. Other vertebrate tracks are those of turtles and, possibly, crocodilians. Due to the decrease in sandstone quarrying in recent decades, many old tracksites are inaccessible today. Additionally, historical descriptions of the tracks were of highly variable quality and often published in remote and today nearly unobtainable sources. Here we provide a catalogue of 13 tracksites compiled from the literature and some new observations. Of these 13 tracksites, only five are still accessible and currently under study. Descriptions of each locality are provided, with a comprehensive compilation of existing data on lithofacies, stratigraphy, palaeogeography and palaeoecology of the Obernkirchen Sandstone and equivalent strata. A short review of the track-bearing lithofacies assemblage indicates that the outcrop areas have distinctly different facies and environments, and, therefore, track-bearing horizons can only be correlated stratigraphically between adjacent outcrops. For this reason, the identification of a megatracksite in the Obernkirchen Sandstone is currently regarded as premature and uncertain. peerReviewed

1. Radioimmunochromatographic analysis of adrenal incubates is a useful method for the characterization of uncommon and unidentified steroid fractions. In incubates of normal adrenals at least seven uncommon fractions were separated. 2. Uncommon and unidentified steroids may react also with antibodies of apparently high specificity. This observation may have practical consequences for in vivo studies. 3. Under pathophysiological conditions such as adrenal regeneration hypertension steroids may be produced by adrenocortical tissue which are not detectable in incubates of normal adrenals.