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The structure of the oviducal sac of Pollicipes cornucopia Leach and of Balanus balanus (L.) has been examined by scanning and transmission electron microscopy. The sac in various species has been given a variety of names and the nomenclature is considered. The outermost part of the sac i.e. , that exterior after extrusion, consists in Pollicipes of uniformly electron-dense material with an even denser boundary layer. Pores lead from the outside to the interior of the sac and they contain remnants of the cytoplasmic filaments. The pores are continued towards the lumen in dense reticulate material projecting in a stalactite-like form towards the inside of the sac. In addition to this dense reticulum, finer reticular material is present which has been shown to be ‘liquid’ before fixation. Numerous fine ‘holes’ — as distinct from true pores — are present in the dense outer layer. The cytoplasmic filaments contain microtubules (or rods), and small vesicles on the cell membrane seem to aggregate to form the coarse reticulum. Similar structures are present in Balanus balanus , but the reticulum is less dense and less concentrated round the pores. Proximally, i.e. , towards the entrance to the oviduct, the pores gradually become reduced in number eventually being virtually absent, and the wall is less organized.

The optical density of the shell-material and that of the underlying pigmented epithelium has been determined for a number of species — littoral, sublittoral, operculate, and pedunculate. In all the species except Lepas fascicularis Ellis & Solander there is a marked change in the attenuation coefficient at a thickness of ≈ 0.20 mm; above and below this thickness log (100 I I 0 ) is linearly related to thickness i.e., the attenuation coefficient is constant. In Balanus crenatus Brug. the optical density appears to reach a constant value independent of thickness. The shell material transmits more at longer wavelengths but the pigmented epithelium acts virtually as a neutral density filter above ≈ 400 nm. Some properties of the pigment are noted and its development relative to the degree of insolation was investigated. The bearing of the results on the light-limitation of endolithic algae and the response of the photoreceptors to light are discussed.

The effect of hypo- and hypersaline media on the development of the embryos of the common cirripedes, Balanus balanoides , (L.), B. crenatus Brug., B. balanus (L.), B. perforatus Brug., Chthamalus stellatus (Poli), and Elminius modestus Darwin has been examined. These species represent littoral and sublittoral, boreo-arctic and warm-temperate, relatively steno- and euryhaline, and steno- and eurythermal forms. The range of salinity over which the embryos would develop to give free-swimming stage I nauplius larvae, no matter at what stage of development the cultures were started, was similar in all species, namely 15–20 to 40%. Low-salinity media cause cytolysis while high salinity media give grossly abnormal embryos which may, however, develop further. There seems little direct relation between salinity tolerance and that of the habitat in which the animals are found; a capacity for acclimation may be more important. The causes underlying the production of abnormalities are discussed.

Because of the small amount of pigmentation the difficulties associated with earlier histological work on Chthamalus stellatus (Poli) are absent in extreme hypobiotic C. depressus (Poli). The formation of the wall plates has been investigated by normal histological techniques and supported by scanning electron microscopy. The wall plates are covered by epicuticle which in its continuity resembles that of Acasta spongites ; the epicuticle is strongly ribbed and the plate has more or less regularly spaced, volcano-like outgrowths. The various cell-types and the part they play in the expansion of the basis and growth of the wall plate are described. A series of ‘bridging’ cells are present and lie between the lower part of the last completely formed ‘scale’ and the basal cells. Growth is considered from the evolutionary point of view and in relation to the forms assumed under natural conditions, in particular to the capacity of the animal to adapt to changes in the rock surface.

The details of morphology of the six naupliar stages of Balanus hesperius are described, the material being referable to the forma laevidomus of Pilsbry. The nauplii are particularly characterized by a long and somewhat slender body and rather stiff appendages, the rami of which are thickened proximally. The general pattern of development conforms to that of other nauplii and is remarkably similar in all balanids. Tables of sizes and setation are given.

New records for Elminus modestus Darwin, and a single one for Balanus eburneus Gould are given for the western coast of France. The local population of B. balanoides (L.) at Arcachon (Gironde) has increased in extent and population density over the past few years; a curious growth form of this species — probably resulting from intense competition with Chthamalus stellatus (Poli) — is described.

The various terms which have been used to describe some quantitative parameters of considerable importance in the reproductive cycle of marine invertebrates are discussed; egg number, fecundity and the metabolic efficiency of egg production are defined in a way applicable to animals such as many crustaceans in which the number of eggs produced is a function of adult size. The variation with tidal level and latitude of egg numbers as well as their changes from one season to another are described and discussed for a number of common cirripedes. Local factors may often obscure latitudinal variations. There is no evidence that egg numbers or fecundity are greatest under poor conditions or at the limits of distribution; indeed the reverse seems to be the case. The metabolic efficiency of egg production, namely, the weight of egg tissue produced per unit time per standard increase in body weight is relatively constant for many operculate species even when they are of different adult or different egg size. It follows that fecundity, the number of eggs produced per unit time per standard increase in body size, is largely a function of egg size. The importance of these factors to the ecology of the animals and to their distribution is discussed.

[La relation entre la teneur en eau et la respiration des tissus du corps, avec reference au cycle de mue, a ete determinee pour Balanus balanoides. La teneur en eau et le quotient respiratoire presentent un cycle en correlation avec le cycle de mue, qui est analogue a celui decrit pour beaucoup d'autres Crustaces. Une comparaison avec d'autres Crustaces montre un maximum plus eleve dans la teneur en eau, ce qui est en relation avec l'absence d'un exosquelette calcifie, la rapidite de la mue et la faiblesse relative de l'accroissement de taille a la mue. Le cycle de respiration ressemble etroitement a celui de Palaemon serratus (de Naples), et d'autres analogies laissent supposer que les mecanismes de controle puissent etre les memes dans les deux cas. Le controle hormonal de ces processus est discute., La relation entre la teneur en eau et la respiration des tissus du corps, avec reference au cycle de mue, a ete determinee pour Balanus balanoides. La teneur en eau et le quotient respiratoire presentent un cycle en correlation avec le cycle de mue, qui est analogue a celui decrit pour beaucoup d'autres Crustaces. Une comparaison avec d'autres Crustaces montre un maximum plus eleve dans la teneur en eau, ce qui est en relation avec l'absence d'un exosquelette calcifie, la rapidite de la mue et la faiblesse relative de l'accroissement de taille a la mue. Le cycle de respiration ressemble etroitement a celui de Palaemon serratus (de Naples), et d'autres analogies laissent supposer que les mecanismes de controle puissent etre les memes dans les deux cas. Le controle hormonal de ces processus est discute.]

An account is given of the further spread of Elminius modestus along the German coast north of the Elbe towards the Danish coast. The population at Cuxhaven has spread to the outer estuary and Balanus balanoides is at several places in danger of extinction. Elminius modestus is now well established in several small harbours as well as on parts of the open coast between Cuxhaven and Dagbuller Hafen. The harbour populations have most probably been established by shipping but some marginal dispersion is taking place at suitable places. The species is absent north of Dagbuller Hafen: it has not yet reached Danish waters either by marginal dispersion or by a vector carrying it into any of the ports. Elminius modestus has not reached the north-eastern German coast.

1. The definition of the word “ecology” is considered and the difficulties — both practical and theoretical — associated with a precise formulation outlined. 2. Ecology as the study of systems consisting of components, or variables, each made up of a number of vectors is discussed. 3. A comparison of the difficulties inherent in the definition with those — less apparent — in abiotic systems is made. 4. The meaning of the word “experimental” is considered and its relation to a series of transformations on a biological system discussed. 5. The meaning — in the restricted sense determined by the definitions given — of experimental ecology and the practical problems it poses are dealt with in some detail. 6. The meaning of “experimental biology” and its relation to experimental ecology, as defined above, is discussed in relation to plant and animal systems. 7. The future of ecology — experimental and otherwise is discussed. 8. The increase in information will call for a greater integrative approach and the possible ways by which this can be achieved are outlined, particularly as they relate to the marine biological sciences.

The seasonal changes in the body weight and composition of two common boreo-arctic species of cirripedes, Balanus balanoides and B. balanus have been followed.At a constant size (age under constant growth conditions) the body weight is closely related to the season. Increase in body weight takes place rapidly during the spring as reserves are laid down. These reserves are subsequently utilized for gonadal development.The changes in B. balanus are more gradual than in B. balanoides and probably reflect differences in the habitat conditions.The reserves, although contributing to the gonads, are not themselves adequate for their total tissue.

The general morphology and detailed histology of the penis of two common boreo-arctic cirripedes, Balanus balanoides (L.) and B. balanus (L.) have been investigated. The penis is a highly extensible, annulated organ beset with four rows of sensory setae. The paired vesiculae seminales unite within the pedicel of the penis to give the single ductus. Distally, the exoskeleton is invaginated into this ductus. Circular muscles are present in the vesiculae seminales but do not continue into the penis. The histology of the ductus epithelium indicates a secretory nature as does that of a specialized group of cells, termed the ‘cushion’, towards the distal end: this group of cells is surrounded by circular muscle bands. Longitudinal muscles extend virtually the whole length of the penis; they give off fibres which are inserted at the junctions of the annulations. The muscles of the pedicel are described. Paired nerves in the pedicel give rise to four in the penis. The sensory innervation of the setae is described. The possible functional relations of the structure to the activities of the penis at copulation and during the emission of semen is discussed.

There is some reduction in oxygen uptake of isolated bodies on starvation when carbohydrate is being utilized.There is a gross discrepancy between the oxygen demand as measured in isolated bodies and the available substrate; respiration is probably reduced during inanition.It is suggested that the moulting cycle is coupled to the metabolic activity in an obligatory fashion rather than being dominated by the kind of hormonal control found in decapods.

The QO2 of three common cirripedes has been measured at four temperatures and on each of four occasions during a year: dissected bodies were used. Statistical analysis indicates that only infrequently is the Q10 weight dependent. Such dependence seems to be related to the nutritional conditions in the environment rather than to the internal state or species habitat. Q10 varies widely even in a given species. In Balanus balanoides there is a marked homeostasis at certain seasons as there is in Chthamalus stellatus at other seasons: Balanus balanus shows somewhat less marked homeostasis. A low Q10 of basal metabolic rate in littoral invertebrates has been observed by others in a variety of animals. The results of some relevant previous work are critically examined and compared with those of the present investigation.

Simultaneous observations with echo sounders and underwater television have been made both in and out of deep scattering layers. All the evidence indicates that, with type of sonic gear used, micro plankton was not responsible for either the observed deep scattering or for detectable echo sequences on the short range equipment. It was possible to “see” for the first time the sound scatters responsible for the typical echo sequences from single animals and to confirm the deductions of Johnson et al. (1956) that individual small fishes give rise to the sort of echo sequences that have been seen in deep scattering layers. The type of echo record and its relation to the number of fish scattering the sound was observed.

The effect of starvation for various periods and also at various times during the development of the ovaries of Balanus balanoides (L.), followed by feeding, has been investigated. The total feeding time to full maturation shows little variation. The time at which the egg masses are laid down can, however, be to some extent manipulated by controlling the starvation period.

One hundred each of stage VI male and female and stage V Calanus finmarchicus were picked at random, and, by means of a projection microscope, measurements made on a number of segments in both metasome and urosome.The stage VI female population was mixed containing 95% of a smallsized population and 5% of a larger size-group. The males constituted a single population.At this time of the season the stage VI male and female metasomes are the same length, but there are differences in the sizes of the individual segments, the most striking of which is that of the headThe stage V animals in many of the measurements could be quite clearly separated into two size-groups of about 50% each and it is suggested that these are potential male and female populations. This separation at 50/50 has been noticed in numerous other collections of stage V, but it shouldbe emphasized that the differences are population differences in regard to those measurements considered.Evidence is presented which shows that the state of the antennules after preservation in 5% neutral formalin is unlikely in stage V animals to be a reliable guide to their sex in the next stage.

It is difficult to determine the weight or nitrogen content of the living tissues of an operculate barnacle without destroying it. It has been customary, there-fore, in ecological work to express growth in terms of various parameters determined from repeated measurements of the shell. Moore (1934) employed shell volume calculated from the height and basal diameters; others (Costlow & Bookhout, 1953, 1956; Mawatari, Hirosaki & Kobayashi, 1954a, b) have used the area of the basis. Most commonly, however, in growth-rate studies the length of the basis measured through the rostro-carinal axis has been used (Hatton, 1938; Barnes & Powell, 1953). Recently, working with animals cultured in the laboratory when the cast of an individual could be obtained subsequent to ecdysis, Costlow & Bookhout (1957) have used the size of the mouthparts as a measure of growth after first establishing their relation to body size. The space, both areal and volumetric, occupied by a sedentary animal is of primary importance in studies of its ecology and measurements of shell-size are, therefore, adequate for many purposes. For some aspects of growth and ecology it is, nevertheless, very desirable that the relation between such parameters and others, more directly connected with the living material, should be established.

Further records of the occurrence of Elminius modestus and changes in its population density at two localities in France, namely, the Baie de St Malo and the St Jean-de-Luz area are given. In the latter region the species is now well-established, although there is some evidence that colonization took place perhaps only a few years ago. The Dordonne estuary may have been the primary site of colonization from which it has been carried southwards as far as Hendaye Plage. The coast between St Quay Portrieux and Cancale now has abundant Elminius in all places where there are suitable habitats: it seems from the available records that this coast had for a long time remained uncolonized. Northward from Granville on the western side of the Cotentin peninsula there is still a scarcity of Elminius. Small populations may be established each summer only to be largely destroyed in the winter. The findings are discussed in relation to previous surveys.

The details of morphology of the six naupliar stages of Balanus nubilis are described. The nauplii are particularly characterized by their large size and in the later stages by a distinctly pentagonal outline. The general pattern of development conforms to that previously found for balanid nauplii. Tables are given of sizes and setation formulae.

An account is given of some observations on Elminius modestus Darwin along the coasts of south and south-west Europe including northern France, Spain and Portugal. The consolidation and extension of the immigrant are discussed.

The structure and innervation of the sensory setae which are present in large numbers on the penis of Balanus balanoides (L.) have been established by scanning and transmission electron microscopy. Each seta contains a small number of sensory dendrites surrounded by an extracellular supporting tube which is presumed to be secreted by the enclosing sheath cell. The dendrites, which distally extend beyond both the sheath cell and supporting tube, terminate at the tip of the seta within a pore-like invagination of the cuticle and thus are in direct contact with the environment. Proximally bundles of dendrites pass into the penis tissue where they are surrounded by several sheath cells. The supporting tube terminates at a point within the body of the penis where a series of intracellular rods arise. The ciliary character of the dendrites is evident in this region, the microtubules being organized into the (9 × 2) +2 pattern. It is deduced that the sensilla are chemosensory; their structure is compared with that of other crustacean sensilla which are presumed to be chemosensory.

1. It is shown that the extraction by 5% trichloracetic acid of glycogen from the tissues of some typical marine invertebrates(Balanus balanoides, Nephtys hombergi, Carcinus maenas, Mytilus edulis) is a function of the homogenization procedure. 2. In agreement with work on rat tissues, glycogen fractions cannot be differentiated by their solubility in cold 5% trichloracetic acid. Total glycogen only need be determined.

This book provides a review covering the basics of marine research, special topics, and emerging areas in fields of oceanography and marine biology. It is intended for researchers and students in all fields of marine science.

The possible contribution of littoral organisms to the zooplankton of inshore waters is largely neglected - particularly in studies of productivity. The relation between the physical dimensions of an inshore system and the relative input from the bottom, the water mass, and the littoral will be considered - largely relative to some common cirripedes. An assessment of the importance of this contribution in terms of both seasonal and non-seasonal events will be considered. A few calculations will show the possible quantitative importance, in some situations at least, of littoral organisms in this respect, particularly when compared with published estimates of the amount of “permanent plankton”. Apart from its general character, “littoral” plankton may be especially important at certain seasons and in particular areas not only in terms of its quantity but also as regards the “quality” of the nutriment it provides for other organisms; it is probably an integral part of some temporary ecosystems.

This worksheet was developed in response to an ever increasing number and intensity of admission and concurrent telephone reviews conducted by third and fourth-party payors. This worksheet was developed as an aid in information gathering for subsequent telephone and other reviews. The left-margin headings evolved from queries for information from the most demanding psychiatric nurse reviewers. When I have fully addressed all the information in my review, it is usually no problem in obtaining certification for admission or continued stay for the patient.