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Holmdalia Robison, 1988 (Family Marjumiidae), was proposed as a monotypic taxon that occurred in mid-Cambrian outer shelf settings in New York and Greenland, with a subsequent report from northwestern Canada. New collections from the Shallow Bay Formation of western Newfoundland record a succession of at least seven species that spans most of the Drumian and all of the Guzhangian stages, and demonstrate that the genus has considerable, previously unrecognized biostratigraphic potential. Older, Drumian species, including the type species, H. punctata (Rasetti, 1967), have longer palpebral lobes and, hence, larger eyes than a group of younger, Guzhangian species. Restudy of the type material shows that previous records of H. punctata outside the type area in New York are misidentifications, but the species does occur in Newfoundland. New Drumian species are H. palpebra and H. tenaga; an additional Drumian species is placed in open nomenclature. New Guzhangian species are Holmdalia glabra, H. lata, and H. tubercula.

The monotypic taxon Xanthotropis n. gen. is established to accommodate Haematotropis media Golovatch, Hoffman & Spelda, 2004, known only from the vicinity of Manaus, Brazil, as it is incompatible with both its originally assigned genus and Aphelidesmus Brölemann, 1898, a suggested alternative. Xanthotropis is defined primarily by minute teeth on paranota 2–4, a sublinear posterior margin of the telson, and an elongated, distally expanded/laminate acropodite. The Aphelidesmidae Brölemann, 1916, range from northeastern Mexico and Tobago to northern Brazil and southwestern Peru; a questionable more-northerly record, from Monterey, Mexico, requires verification with fresh material. One of two families of the polydesmidan superfamily Platyrhacoidea (Leptodesmidea), Aphelidesmidae comprises two subfamilies, the nominate and Amplininae Hoffman, 1954. The latter has been addressed by several authors, and we here review Aphelidesminae by providing full synonymies, a literature review, and a key to its four genera: Aphelidesmus Brölemann, 1898; Haematotropis and Ochrotropis, both by Jeekel, 2000; and Xanthotropis n. gen.

Plant Conservation Division, Korea National Arboretum, Pocheon 487-829, KoreaAbstract - Abeliophyllum distichum is a monotypic taxon of Oleaceae and endemic to Korea. A comprehensive study on embryogeny and fruit and seed coat ontogeny in Abeliophyllum was carried out via microtome and light microscopy. The fertilization occurs during mid– to late April and embryo matures by early July. The embryo development follows the general fashion from globular embryo – transition embryo – heart shaped embryo – torpedo embryo – walking-stick embryo to mature embryo. The pericarp clearly differentiates into three histological zones: exocarp, mesocarp, and endocarp. The young seed comprises 10-12 cells thick seed coat and the mature seed coat comprises an exotesta, 6-8 mesotesta and an endotesta. Any crystals, phenolic-like compounds, idioblasts, and the sclereids are not found in pericarp as well as seed coat. An overall development confirms Solanade type of embryogenesis in Abeliophyllum. The endocarp becomes more prominent in mature fruit and all the layers of endocarp are highly lignified. On the basis of mechanical layer the seed coat is of exotestal type.

The purpose of this application, under Article 23.9.3 of the Code, is to conserve the widely used generic name Eusparassus Simon, 1903 for a well-known huntsman spider genus from Africa and Eurasia currently with 30 known valid species. The name is threatened by its little-used senior synonym Cercetius Simon, 1902. Simon (1902) established the name Cercetius for a monotypic taxon based on a juvenile specimen of C. perezi Simon, 1902. The generic name has never been used as valid except in catalogues and other lists. The discovery of adult specimens of C. perezi in the type locality and nearby regions supports the synonymy of Cercetius with Eusparassus. The putative junior synonym Eusparassus is however a longaccepted name and it should be conserved to maintain stability of nomenclature in this taxonomic group.

Aristofolia Ayala-Landa, a valid genus of Asilinae (Diptera, Asilidae). The robber fly genus Aristofolia Ayala-Landa, 1978 is a monotypic taxon of Asilinae. The status of Aristofolia is revalidated, and addenda to the original description of the genus is provided. The habitus, wings, male and female terminalia are described and illustrated.

The Southern Hemisphere contains many monotypic taxa, for which phylogenetic relationships are important to illuminate biogeographical history. The monotypic genusLyalliais endemic to the sub-Antarctic Iles Kerguelen. A close relationship with another monotypic taxon, the New Zealand endemicHectorella, was proposed. They share a dense cushion growth habit with small coriaceous leaves that lack stipules. The solitary flowers are bicarpellate with two sepals, 4–5 petals, 3–5 stamens and a bifid style. The fruit is an indehiscent capsule with 1–5 seeds. The flowers ofLyallia kerguelensisare hermaphroditic with four petals and three stamens whereas the flowers ofHectorella caespitosaare female, male or hermaphroditic, with five petals and five stamens.Lyallia kerguelensisis rare on Kerguelen, whereasHectorella caespitosais confined to the South Island of New Zealand. Our phylogenetic analysis oftrnK/matK intergenic spacer andrbcL sequences provides evidence supporting a close relationship betweenLyalliaandHectorella. The two species form a well-supported clade that is nested within the Portulacaceae. Divergence estimates suggest they shared a common ancestor during the late Tertiary long after the fragmentation of Gondwana. Such relationships underscore the importance of transoceanic dispersal and extinctions for plant evolution in the Southern Hemisphere.

The riodinid Rhetus belphegor (Westwood) (n. comb., previously in the genus Nirodia) is a critically endangered butterfly confined to the “campos rupestres”; a high-altitude rocky outcrop vegetation from southeast Brazil. The aim of this study is to unveil its biology and evaluate its systematic position. Based on museum data and public contribution of data (in the context of citizen science), R. belphegor is restricted to the “Espinhaço Mountain Chain”, and occurs exclusively above 1000 m. Adults were found resting upside down on rock walls. Females searched for host plants during the hottest hours of the day, depositing 1–2 eggs on leaves of the herbaceous subshrub Microstachys serrulata (Euphorbiaceae). The non-myrmecophilous larvae developed through six instars and the developmental time from egg to adult was ~50 days. Larvae are covered with abundant setae. Morphology of immature stages and molecular phylogenetic analysis showed that Nirodia is part of Rhetus, justifying the generic change. Our data supports that Nirodia is the only species in its clade associated with high mountains, in contrast to its lowland congeners. The description of the immature biology and clarification on its systematic position are essential steps for the establishment of better and more effective conservation efforts for this magnificent Brazilian butterfly., LAK was supported by CNPq (163119/2013-9) and CAPES (3200-14-0). NS was supported by CNPq (141254/2013-0) and CAPES (3700/14-3). AVLF thanks the CNPq (fellowship 302585/2011-7), the National Science Foundation (DEB-1256742) and the BIOTA-FAPESP Program (11/50225-3). NW acknowledges funding from the Academy of Finland (265511). This publication is part of the RedeLep “Rede Nacional de Pesquisa e Conservação de Lepidópteros” SISBIOTA-Brasil/CNPq (563332/2010-7), of the project “Identificação Molecular de Biodiversidade de Invertebrados Terrestres” (Grant 564954/2010-1) included in the “Rede Nacional de Identificação Molecular da Biodiversidade—BR-BoL” (MCT/CNPq/FNDCT 50/2010), and of the collaborative grant ‘Dimensions US-BIOTA São Paulo: A multidisciplinary framework for biodiversity prediction in the Brazilian Atlantic forest hotspot’, US NSF, NASA and FAPESP (Grant 2013/50297-0).

Four new and three known oleanane-type saponins have been isolated from the methanolic extract of Phryna ortegioides, a monotypic and endemic taxon of Caryophyllaceae. The structures of the new compounds were determined as gypsogenic acid 28-O-β- d -glucopyranosyl-(1→2)-O-β- d -glucopyranosyl-(1→6)-O-β- d -glucopyranosyl ester (1), 3-O-α- l -arabinofuranosyl-gypsogenic acid 28-O-β- d -glucopyranosyl-(1→3)-O-[β- d -glucopyranosyl-(1→6)]-O-β- d -glucopyranosyl ester (2), 3-O-α- l -arabinofuranosyl-gypsogenic acid 28-O-β- d -glucopyranosyl-(1→3)-O-[β- d -glucopyranosyl-(1→2)-O-β- d -glucopyranosyl-(1→6)-O-]-β- d -glucopyranosyl ester (3), 3-O-α- l -arabinofuranosyl-16α-hydroxyolean-12-en-23,28-dioic acid-28-O-β- d -glucopyranosyl-(1→3)-O-[β- d -glucopyranosyl-(1→2)-O-β- d -glucopyranosyl-(1→6)]-O-β- d -glucopyranosyl ester (4). Their structures were established by a combination of one- and two-dimensional NMR techniques, and mass spectrometry. Noteworthy, none of isolated compounds possesses as aglycone moiety gypsogenin, considered a marker of Caryophyllaceae family. The cytotoxic activity of the isolated compounds was evaluated against three cancer cell lines including A549 (human lung adenocarcinoma), A375 (human melanoma) and DeFew (human B lymphoma) cells. Only compound 6 showed a weak activity against A375 and DeFew cell lines with IC50 values of 77 and 52 μM, respectively. None of the other tested compounds, in a range of concentrations between 12.5 and 100 μM, caused a significant reduction of the cell number.

The major diagnostic features for erecting the red algal subfamily Choreonematoideae (Corallinales) were a combination of 1) absence of both cell fusions and secondary pit connections, 2) conceptacle roof and wall comprised of a single cell layer, and 3) presence of tetrasporangial pore plugs within a uniporate conceptacle in the monotypic taxon Choreonema thuretii (Bornet) Schmitz. Because this alga is a parasite, the absence of secondary cell connections is most likely an adaptation to a reduced thallus. This study shows that all conceptacles are not composed of a file of cells but rather a single layer of epithallial cells that are underlain by a thick layer of calcified acellular material; both epithallial cells and the calcified layer are produced by peripheral sterile cells. Although the outermost tetrasporangial pore canal is uniporate, there is a calcified acellular multiporate plate recessed just below the rim. The plate is produced by interspersed sterile cells and is continuous with the calcified layer supporting the conceptacle. These unique structures are likely due to parasitism rather than to the ancestral state. Based on these results and a reexamination of published micrographs depicting lenticular cells in Austrolithon intumescens Harvey et Woelkerling, we propose that both subfamily Choreonematoideae and Austrolithoideae are closely allied with subfamily Melobesioideae. This distant relationship to its host (Corallinoideae) plus a combination of unique conceptacle and unusual type of parasitism indicates that C. thuretii is an alloparasite and that it is likely the most ancient red algal parasite studied to date.

Summary Heterostyly is clearly confirmed in the Korean endemic, monotypic taxon Abeliophyllum distichum Nakai (Oleaceae) by studies of plants from two geographically isolated populations. Variation in the hitherto unreported floral morphological aspects including an extended study of pollen grains of A. distichum in association with distyly were studied and described in details by using stereo-microscopy, LM and SEM. In this plant styles are always significantly longer in pin flowers than in thrum flowers, and the same is also true for the size of stigma including stigmatic papillae between two morphs ( P P P P Apis sp. and Lasioglossum sp. (both in Apidae) were found as flower visitors in A. distichum . Floral dimorphism of A. distichum with respect to heterostyly is also briefly discussed.

The Bornean Oxypilinae species previously included in the genus Hestiasula Saussure, 1871 are revised. External morphology and genital characters of Sundaian taxa differ considerably from the Indian type species H. brunneriana Saussure, 1871, necessitating taxonomic and nomenclatural changes. The genus Catestiasula Giglio-Tos, 1915 is reinstated. It is characterized by the apomorphic partial fusion of the dorsal and ventral laminae of the left phallomere, and by the complete reduction of the apical process. It is represented on Borneo with two species, C. nitida (Brunner de Wattenwyl, 1893) and C. moultoni Giglio-Tos, 1915. An additional species, C. seminigra (Zhang, 1992) n. comb. occurs in continental SE Asia. Two new genera are described, united by the lack of styli, the presence of dorsal carinae on the subgenital plate, and the unique morphology of the dorsal lamina of the left phallomere, but differing in the morphology of head and forelegs. Astyliasula gen. nov. accommodates A. phyllopus (De Haan, 1842) n. comb. and related species from the Sunda Islands and continental SE Asia: A. basinigra (Zhang, 1992) n. comb., A. hoffmanni (Tinkham, 1937) n. comb., A. javana (Beier, 1929) n. comb., A. major (Beier, 1929) n. comb., A. inermis (Wood-Mason, 1879) n. comb., and A. wuyshana (Yang & Wang, 1999) n. comb.. Hestias sarawaca Westwood, 1889 is removed from synonymy with A. phyllopus and reinstated as A. sarawaca (Westwood, 1889) n. comb.. The monotypic taxon Pseudohestiasula borneana gen. nov. sp. nov. is erected for a Bornean endemic more closely related to Astyliasula than to the other genera. Hestiasula is now restricted to H. brunneriana and related species from India and adjacent countries. The tribe Hestiasulini Giglio-Tos, 1915 stat. rev. is proposed for all genera more closely related to Hestiasula than to other Oxypilinae, that is Hestiasula , Ephestiasula , Catestiasula , Astyliasula , and Pseudohestiasula . New data on the ecology and distribution of all Bornean Hestiasulini as well as a key to the Oxypilinae of Borneo are provided.

Using the cladistic method of Hennig a phylogenetic system of Clavatoraceae (fossil Charophyta) is proposed. A number of new combinations arise from this study. The family Clavatoraceae is composed of three monophyla: (1) the Atopocharoidae, which are defined by presenting a utricle with a radial symmetry formed by the superposition of two whorls of spine-shaped bracts and includes traditional members plus traditional Echinocharoideae; (2) the Dictyoclavatoroidae, a monotypic taxon formed by Dictyoclavator fierii , which includes all traditional species of the genus and is defined by a utricle composed of a dense tissue of sub-polygonal cells; and (3) the Clavatoroidae, defined by showing a “Ringstruktur” calcification and a gyrogonite surrounded by a nodular layer, includes traditional members of the subfamily without Dictyoclavator . Atopocharoidae include five taxa: Diectochara andica, Echinochara spinosa, E. pekii, Globator maillardii and Atopochara trivolvis . Traditional systematics created a large number of anagenetic taxa within some of these species. Although these traditional taxa are biostratigraphically useful, they are by no means equivalent to evolutionary species. The ancestral species of the subfamily is at present unknown. D. andica, E. spinosa, E. peckii and A. trivolvis are considered as terminal taxa of the stem line. E. peckii is proposed as the ancestral species of G. maillardii . Clavatoroidae include an ancestral species ( Nodosoclavator bradleyi ) and four genera each one with a different utricle architecture (Bauplan): (1) Clavator is defined by the apomorphy “bracts adjacent to the phylloid bearing fans of spine cells”. It is formed by six species plus the ancestral species and includes traditional members of Clavator, Flabellochara, Clypeator, Triclypella, Lucernella and Septorella . (2) Ascidiella is defined by the apomorphies “external layer of utricle constituted by two nodes of the phylloid” and “bracts bearing rosettes of petal-shaped cells”. It is formed by four species plus the ancestral species and includes the traditional genera Ascidiella and Embergerella . (3) Hemiclavator is defined by the apomorphy “external layer of utricle consisting of one or two whorls of triangular-shaped cells directly attached to the phylloid”. The genus contains one species and its ancestor and includes the traditional genus Hemiclavator and the species Nodosoclavator adnatus . (4) Pseudoglobator is defined by the apomorphy “external layer of utricle constitued of filiform cells radiating from the basal node”. It contains one species and its surviving ancestor and includes the traditional taxa Pseudoglobator fourcadei and P. paucibracteatus .

The wild silkmoth genus Sinobirma Bryk, 1944 is a poorly known monotypic taxon from the eastern end of the Himalaya Range. It was convincingly proposed to be closely related to some members of an exclusively Afro-tropical group of Saturniidae, but its biogeographical and evolutionary history remains enigmatic. After examining recently collected material from Tibet, northern India, and northeastern Myanmar, we realized that this unique species, S. malaisei Bryk, 1944 only known so far from a few specimens and from a very restricted area near the border between north-eastern Myanmar and the Yunnan province of China, may in fact belong to a group of closely related cryptic species. In this work, we combined morphological comparative study, DNA barcoding, and the sequences of a nuclear marker (D2 expansion segment of the 28S rRNA gene) to unequivocally delimit three distinct species in the genus Sinobirma, of which two are described as new to science: S. myanmarensis sp. n. and S. bouyeri sp. n. An informative DNA barcode sequence was obtained from the female holotype of S. malaisei--collected in 1934--ensuring the proper assignation of this name to the newly collected and studied specimens. Our findings represent another example of the potential of coupling traditional taxonomy and DNA barcoding for revealing and solving difficult cases of cryptic diversity. This approach is now being generalized to the world fauna of Saturniidae, with the participation of most of the taxonomists studying these moths.

The taxonomic status of various species of Dekkera, Brettanomyces and Eeniella was examined by electrophoretic comparison of enzymes, by deoxyribonucleic acid homology and by physiological characterization. These studies demonstrated that two teleomorphic Dekkera species, D. anomala and D. bruxellensis (synonym D. intermedia), and four anamorphic Brettanomyces species, B. anomalus (synonym B. claussenii), B. bruxellensis (synonym B. abstinens, B. custersii, B. intermedius, B. lambicus), B. custersianus and B. naardenensis, can be recognized. The anamorphic genus Eeniella remained as a separate, monotypic taxon.

Background The genus Micronycteris is a diverse group of phyllostomid bats currently comprising 11 species, with diploid number (2n) ranging from 26 to 40 chromosomes. The karyotypic relationships within Micronycteris and between Micronycteris and other phyllostomids remain poorly understood. The karyotype of Micronycteris hirsuta is of particular interest: three different diploid numbers were reported for this species in South and Central Americas with 2n = 26, 28 and 30 chromosomes. Although current evidence suggests some geographic differentiation among populations of M. hirsuta based on chromosomal, morphological, and nuclear and mitochondrial DNA markers, the recognition of new species or subspecies has been avoided due to the need for additional data, mainly chromosomal data. Results We describe two new cytotypes for Micronycteris hirsuta (MHI) (2n = 26 and 25, NF = 32), whose differences in diploid number are interpreted as the products of Robertsonian rearrangements. C-banding revealed a small amount of constitutive heterochromatin at the centromere and the NOR was located in the interstitial portion of the short arm of a second pair, confirmed by FISH. Telomeric probes hybridized to the centromeric regions and weakly to telomeric regions of most chromosomes. The G-banding analysis and chromosome painting with whole chromosome probes from Carollia brevicauda (CBR) and Phyllostomus hastatus (PHA) enabled the establishment of genome-wide homologies between MHI, CBR and PHA. Conclusions The karyotypes of Brazilian specimens of Micronycteris hirsuta described here are new to Micronycteris and reinforce that M. hirsuta does not represent a monotypic taxon. Our results corroborate the hypothesis of karyotypic megaevolution within Micronycteris, and strong evidence for this is that the entire chromosome complement of M. hirsuta was shown to be derivative with respect to species compared in this study.

The status of the monotypic taxon Haplogonopus (Verhoeff, 1941), proposed for a disjunct Tanzanian spirostreptoid, is reviewed in light of two additional species, which despite different peripheral appearances, are referable to this genus on the basis of genitalic features. Haplogonopus inflatannulus Verhoeff is redescribed from topotypic material, the nominal species Charactopygus jeanneli (Brolemann, 1920) is relocated in Haplogonopus (n. comb.), and the new species H. cin- gulatus is described from the Rondo Plateau in southeastern Tanzania. A terminology for the modified paraproct structure (“Charactopygus-Bildung”) of spirostreptids is proposed.

The Rocky Mountain Astragalus molybdenuis s.l. comprises A. molybdenus from Colorado, A. shultziorum from Wyoming, and A. lackschewitzii sp. nov. endemic to Montana. These three species are determined to be closely related to the species of Astragalus sect. Polares. Section Minerales, formerly a monotypic taxon that accommodated A. molybdenus in the Phacoid Phalanx next to sect. Astragalus, is now synonymized with sect. Polares. Supporting evidence comes from morphometric and cladistic analysis of morphological and chloroplast DNA restriction site data, and is consistent with findings reported elsewhere on sequence variation of the internal transcribed spacers that flank 5.8S nuclear ribosomal DNA. A previously overlooked attribute of A. molybdenus s.l. (the mature pod, which is deciduous from a marescent, ventrally ruptured calyx) is used to pinpoint the relationships of this species group to the piptoloboid Homalobi subgroup of Neo-astragalus. Additionally, chloroplast DNA sequences are exceptionally divergent among populations, on the order of 1.5-2.0%, and this evidence is used in part to support the recognition of three constituent species within A. molybdenus s.l.

Padangia pulchra Werner, 1924, a forgotten monotypic taxon from Sumatra, is reexamined and found to be distinct from all known colubrid genera. Comparison with colubrids of possible affinity indicates that Padangia is most closely related to the monotypic Collorhabdium williamsoni Smedley of Malaya. The visceral anatomy of Padangia and Collorhabdium is described. As Werner's generic epithet is preoccupied by the mollusc Padangia Babor, 1900, Etheridgeum is proposed as a replacement name. Etheridgeum pulchrum is redescribed and illustrated.

Though the Lumbriculidae is a monotypic taxon including Kurenkovia, there is no support from cladistic analyses for the Kurenkovidae. The unusual nature of the vasa deferentia, which run between the epithelial and muscular layers of the body wall as in some Haplotaxidae and Glossoscolecidae, may affect that decision. The Dorydrilidae is a sister-group to the Lumbriculidae. Lamprodrilus and the Lake Baikal endemic genera are now seen as advanced forms which may have given rise to some Asian and Pacific rim North American taxa. Several of the genera best represented in Europe have the plesiomorphic pattern of the reproductive system, with gonads in GI–GIII but atria limited to GII, so that two pairs of vasa deferentia are associated with them. This pattern is shared with the Branchiobdellida, and whereas median fusion of the atria has happened independently in the two taxa, these two taxa may arise from a common ancestor despite the degree of specialization to an epizooic habit in the branchiobdellidans. Most subgeneric taxa entered into the analyses are grouped at least close to their congeners, with the exception of Neoscolex, which may be more closely related to the pair of Kincaidiana species than to Styloscolex. Rhynchelmis may have an origin distinct from that of Lamprodrilus, Kincaidiana, and Neoscolex, as the loss of the anterior testes may be convergent and not monophyletic as suggested here.

SUMMARY1. Campelia zanonia, a monotypic taxon of Tradescantiae-Hexandrae, has 2n = 16 chromosomes. The karyotype consists of two pairs of long chromosomes with submedian centromeres, four pairs of medium-sized ones with subterminal centromeres among which one pair has the satellites, and two pairs of short chromosomes with subterminal centromeres.2. Neither multivalents nor chains of bivalents have been observed during meiosis. Therefore it is neither a polyploid nor a case of segmental Interchange as was previously described. It is just a normal diploid.

Palaenigma wrangeli(Schmidt) is a finger-sized fossil with a tetraradiate conical skeleton; it occurs as a rare component in fossiliferous Upper Ordovician strata of the eastern Baltic Basin and is known exclusively from north Estonia. The systematic affinities and palaeoecology ofP. wrangeliremained questionable. Here, the available specimens ofP. wrangelihave been reexamined using scanning electron microscopy and x-ray computed tomography (microCT). Additionally, the elemental composition of the skeletal elements has been checked using energy dispersive X-ray spectroscopy. The resulting 2D-, and 3D-scans reveal thatP. wrangeliconsists of an alternation of distinct calcium phosphate (apatite) lamellae and originally organic-rich inter-layers. The lamellae form four semicircular marginal pillars, which are connected by irregularly spaced transverse diaphragms. Marginally, the diaphragms and pillar lamellae are not connected to each other and thus do not form a closed periderm structure. A non-mineralized or poorly mineralized external periderm existed originally inP. wrangelibut is only rarely and fragmentary preserved.P. wrangelioften co-occurs with conulariids in fossil-rich limestone with mudstone–wackestone lithologies. Based on the new data,P. wrangelican be best interpreted as a poorly mineralized conulariinid from an original soft bottom habitat. Here the new conulariinid family Palaenigmaidae fam. nov. is proposed as the monotypic taxon forP. wrangeli.

In Points of View (Syst. Zool., 16, 1967: 174-175), James S. Farris objected to our use of a fixed set of characters in the solution to Gregg's Paradox that we proposed (Roger Buck and David L. Hull, "The Logical Structure of the Linnaean Hierarchy," Syst. Zool., 15, 1966:97-111). We agree with Farris that definitions of the names of many taxa in terms of single, fixed sets of characters is impossible. The exposition in the main body of our paper was couched in such traditional terms for the sake of simplicity (but see pages 106-107 of our paper). Instead, some form of definition by cluster analysis is necessary (see David L. Hull, "The Effect of Essentialism on Taxonomy," The Brit. Jour. Phil. Sci., 15, 1965:314-326 and 16, 1965:1-18). Farris's suggested use of the nomenclatural type as a focus for an overall similarity relation r is one possible variation of definition by cluster analysis (see Douglas Gasking, "Clusters," Australasian Review of Philosophy, 38, 1960:1-36). Farris also says that any difference in the definitions of the name of a higher taxon and its single included monotypic taxon "would necessarily be conjectural." It is true that differences in the clusters could be only partially specified in advance, but it is our understanding that the purpose of monotypic classification in evolutionary taxonomy is to indicate extreme divergence where there has been no diversification. If so, then to the extent that monotypic classification is justified in the first place, to that extent the appropriate definitions can be given. The rational basis for our proposed solution to Gregg's Paradox is precisely that upon which monotypic classification rests. DAVID L. HULL ROGER BUCK Philosophy Department, University of Wisconsin at Milwaukee, Milwaukee, Wisconsin