ALBERT

Description: A systematic study has been made of the Paguridea (exclusive of the Lithodidae) from northwestern North America. In addition to the redescriptions of all known species, two subgenera are herein raised to generic rank and a new genus is described. Several systematic problems have been resolved, and have resulted in the suppression of several specific names familar to North American carcinologists.

Description: The migration of G. zaddachi in La Slack, a small stream on the French Channel coast, and some physico-chemical properties of the river are discussed.\nIn laboratory experiments, the influence of the Cl- and Ca++ concentration on the survival-rate and reproduction of G. zaddachi was investigated. A raise in the Cl- concentration of the medium caused a significant improvement of the survivalrate. A raise in the Ca++ concentration also gives, although not significant, a higher survival-rate.

Description: An account is given of the collembolan fauna of the Greek island Rhodos, from material collected in early spring 1970. Altogether 52 taxa were recognized, constituting the first faunal list for the Greek isles.\nSix new species are described in this material, viz. Lathriopyga hellenica, , Folsomides nanus, Pseudosinella ciliata, Orchesella sporadica, Deuterosminthurus pandayi and Dicyrtomina (Calvatomina) articulata; moreover the new subspecies Acherontiella bougisi rhodia and Deuterosminthurus sulphureus mediterraneus, and the new forma Deuterosminthurus pallipes fenyesi f. pallida. Heteromurus sexoculatus Brown, 1926, is reduced to a form of H. major (Moniez, 1889), Deuterosminthurus fenyesi Stach, 1926, is reduced to a subspecies of D. pallipes Bourlet, 1843. A lectotype is designated for D. p. fenyesi. Folsomides anophthalamis Hepburn & Woodring, 1964, is synonymized with F. americanus Denis, 1931; Oncopodura ambigua Christiansen, 1958, is synonymized with O. crassicornis Shoebotham, 1911; Seira pillichi graeca Ellis, 1966, and S. petrae Jacquemart, 1973, are synonymized with S. ferrarii Parona, 1888. A key is presented to the species of Folsomides, and to the European species of Deuterosminthurus. The Sminthurus viridis complex is represented by S. viridis (Linnaeus, 1758), and a peculiar form of S. nigromaculatus Tullberg, 1872, that presumably represents a separate taxon.

Description: 1. The migration of two sympatric estuarine species has been studied over a period of one year in the estuary of the river Dourduff, a small river draining into the Bay of Morlaix (Brittany, France). One species, Gammarus zaddachi, is a boreal species and the other, Gammarus chevreuxi, is a lusitanian species. Both species live near the limits of their distribution area. 2. Both species show a migration pattern with an anadromous and a catadromous phase. The migration is an active process. The animals use the tidal movements for their upstream and downstream migration. 3. Migration activities of both species show a diurnal rhythm, the activity peak occurring at night. 4. Downriver migration of both species can be observed throughout the whole year. Upstream migration, however, only takes place during periods with high water spring tide. During these periods the stream reverses direction and water with higher salinities enters the limnic parts of the river. 5. Per night the maximum numbers of anadromous and catadromous migrating individuals caught in a net of 30 X 50 cm were 30,000 and 800,000 respectively for G. chevreuxi. For G. zaddachi these numbers are considerably lower. 6. In both species the composition of the samples from upstream and downstream catches were different. In general, upstream migrating animals are smaller and younger than downstream migrating individuals. 7. G. zaddachi invades the limnic reaches of the river only when water temperatures drop below 6\xe2\x80\x948\xc2\xb0 C, a situation occurring for a period of only a few weeks. 8. G. zaddachi reproduces only during the winter months when water temperatures are relatively low. Reproduction takes place in areas with constant or at least periodical influence of mixohaline waters. In the limnic reaches of the Dourduff reproduction is never observed. 9. G. chevreuxi migrates farther upstream than G. zaddachi. It can stay in completely fresh water for more than four months. 10. G. chevreuxi can reproduce during the whole year. Reproduction has never been observed in completely fresh areas, although downstream migrating ovigerous females can be found. 11. In a series of laboratory experiments, survival rates and reproduction capacity were determined under various different temperature/salinity conditions. 12. Temperature has a strong influence on the salinity tolerance of G. zaddachi. At 5\xc2\xb0 C the mortality rate in river water is comparable to that under optimal salinity conditions. At higher temperatures the mortality sharply increases at lower salinities. 13. Increasing salinity as well as decreasing temperatures have a positive influence upon the reproduction rate of G. zaddachi. In rearing experiments no reproduction has been observed in limnic (= natural) water of the Dourduff, at 5\xc2\xb0 C. 14. For G. chevreuxi the situation is different. At 5\xc2\xb0 C survival is low at all salinities. Under brackish conditions (0.8\xe2\x80\xb0 and 8.0\xe2\x80\xb0 Cl) a rise in temperature results in a higher survival rate. In fresh water however (0.08\xe2\x80\xb0 Cl), rise of temperature causes a higher mortality rate. 15. In rearing experiments G. chevreuxi does not reproduce in completely fresh water. Under mixohaline conditions reproduction has been observed at all temperatures examined. 16. The reproduction cycle of the two species is shown in diagrammatic models.

Description: A redescription is given for five formae of Cavolinia tridentata and four formae new to science are described. The distribution of the species is given and the zoogeography of the formae is discussed.

Description: Niphargus puteanus (Koch in Panzer, 1836) is redescribed, in accordance with the criteria formulated by the \xe2\x80\x9cFirst International Colloquium on the Genus Niphargus\xe2\x80\x9d, at Verona (1969). The redescription is based on material collected near the type-locality, Regensburg (German Federal Republic). A neotype, and a restricted type-locality, are indicated.

Description: A biography of H. E. van Rijgersma is given, with the genealogical register of his family. The zoological and historical literature, in which he was mentioned, is discussed. Van Rijgersma\'s illustrated manuscripts on botany (1868) and malacology (1875) of St. Martin, and his correspondence with malacologists, were discovered in the United States and studied. The recent mollusk fauna of St. Martin is summarized, consisting of 550 species, of which 136 are new to the fauna of that island.

Description: In a series of experiments with G. pulex, G, duebeni celticus and G. duebeni duebeni populations, pure or mixed, their tolerances for several temperature/salinity conditions have been determined. Tested were 100%, 10%, 1% and 0.1% seawater in combination with temperatures of 5\xc2\xb0, 10\xc2\xb0 or 15\xc2\xb0 C. In general all species preferred the 5\xc2\xb0C conditions above those with a higher temperature, and the middle salinity range (1% for G. pulex, 1% and 10% for G. d. celticus and G. d. duebeni) above the lower or higher salinities.\nIn nearly all situations tested G. pulex had a lower survival rate than G. d. celticus and G. d. duebeni.\nNotwithstanding the sometimes unfavourable conditions for G. pulex, this species can compete successfully with G. d. celticus under most of the experimental conditions, but the interspecific relations between G. pulex and G. d. duebeni end in the competitive exclusion of the first species. These results support two theories: (1) G. pulex is able to compete successfully with G. d. celticus and to expel the latter from its niche, and (2) G. d. duebeni is able to invade freshwater and to establish inland populations.\nThe differences demonstrated between G. d. celticus and G. d. duebeni are an argument for a different development and different capabilities of both subspecies.\nSterile interspecific matings between G. pulex and both subspecies of G. duebeni are temperature dependent and do not play a major role in the interspecific relations connected with competition.

Description: A quantitative macroscopic and microscopic investigation was performed upon the placenta of the sheep.\nMacroscopic data were obtained from 235 cases of single pregnancy, 285 cases of twin pregnancy, 45 cases of triplet pregnancy, and from one case of quadrulet pregnancy. Macroscopic data obtained include: weight of the uterine horns, weight of the fetal membranes, weight of the total cotyledonary mass, and weight of the fetus.\nMicroscopic data were mainly obtained from twin pregnancies (about 30 placentas in each of the nine age groups, group I being excluded from this investigation). The following microscopic data were calculated: vascularization of the caruncles (being the maternal component), degree of branching of the villi, total villous surface, vascularization of the villi, and total villous blood volume.

Description: For the \xe2\x80\x9cSagitta serratodentata-group\xe2\x80\x9d, synonymy, morphology and biometrical data are given of S. serratodentata, S. tasmanica and S. pacifica. S. serratodentata is divided into two subspecies, S. serratodentata serratodentata and S. serratodentata atlantica. The zoogeography of all six taxa of the \xe2\x80\x9cS. serratodentata-group\xe2\x80\x9d is discussed.