174 SUMMARY OF CURRENT RESEARCHES RELATING TO 



e - Crustacea. 



Life- History of Cladocera.* — Robert Gumey gives a general 

 account of the reproduction and life-history of Cladocera. He dis- 

 cusses the occurrence of the sexual periods in different years, and is 

 disinclined to agree with Weismann that the appearance of the sexual 

 individuals is unaffected by external conditions. He believes that 

 further experiments will show a direct connection of the sexual cycle 

 with the season, determined probably by the average temperature, and 

 that the sexual individuals of the second (autumn) cycle are not wholly, 

 or even largely, derived from the resting eggs of the previous cycle, 

 but are their descendants by agamic reproduction. 



Respiration in Sand-Burrowing Crabs.t — W. G-arstang discusses 

 the various ways in which burrowing crabs draw up a sufficient supply 

 of water free from particles of sand and mud. In the common shore- 

 crab and in Portunidae the claws, together with the marginal spines of 

 the shell, form a sieve. In Calappa and others without filtering spines, 

 there are crest-like expansions, divided into spines and notches on the 

 upper edge of the claws themselves. In Corystes the water is sucked in 

 in front along a temporary tube formed by the juxtaposition of the 

 long antennae, which bear a double row of curved hairs. When Atele- 

 cyclus lies in the surface layer, it uses its antennae as a funnel ; when it 

 goes deeper, it forms a reservoir beneath the body by folding in its 

 claws and other legs. The water percolates between the chelipeds and 

 the carapace, and through the filters formed by the interlocking rows of 

 hairs on the legs. 



Decapods collected by the 'Princess Alice.' J — E. L. Bouvier 

 calls attention to some of the interesting forms collected in 1905 by the 

 Prince of Monaco. The list includes the rare Peneid Hepoinadus tmer 

 Smith ; a Pagurid, with aciculate ophthalmic scales, Anapagurus Ictvis 

 v&T.longispina Edw.et Bouv. ; an Eryonid, Polychetes eryoniformis sp. n. ; 

 a very remarkable abyssal form, Eryoneicus alberti sp. n. ; a beautiful red 

 Peneid, Gennadas elegans Smith ; and another abyssal form, Glaucothoe 

 peroni Edw. 



Reproduction in Copepods.§ — E. Wolf has made a very exhaustive 

 study of the biology of reproduction in the Copepods of Wurtemberg. 

 The locality is rich in Cyclopidae and Harpactidae, and, on the contrary, 

 poor in Centropagidae. All the native species show regular times of 

 reproduction — i.e. all the members of a species reproduce and die about 

 the same time, making place for the new generation, although special 

 conditions, such as drought, want of food, etc., may disturb these rela- 

 tions. Nearly related species in the same habitat show somewhat similar 

 periods of reproduction, while, on the other hand, the same species in 

 different habitats may in the same year give rise to a different number 

 of generations. A single species may exhibit varieties with entirely 

 different reproductive modes. All Copepods in unfavourable seasons are 



* Trans. Norfolk and Norwich Nat. Soc, viii. part 1 (1905) pp. 44-58 (4 figs 

 and 2 tables.). t Tom. cit., pp. 22-4. 



X Comptes Rendus, cxli. (1905) pp. 644-7. 

 § Zool. Jahrb. Abt. Syst., xxii. (1905) pp. 101-280 (2 pis., 1 fig.). 



