ENTOMOSTRACA

Goodsir (Edinb. New Philosoph . Journ. xxxv, p. 102) has investigatedin the Eirth of Forth what the fishermen there term “ Maidre.” It is con-stituted of vast and connected masses of living animals, among whichAmphipoda, Cirripedia, and Acalephse occur abundantly, but is principallycomposed of Entomostraca. These waters are invaded not only by immenseshoals of “ Coal-fish,” and small ones of Herrings, but also by variousCetaceans, particularly Dolphins, and Porpoises , and even the Rorqual is occa-sionally seen. The author thinks that these Cetaceans are not in pursuit ofthe fish in order to feed upon them, but that they participate with them inthe food afforded by the “ Maidre,” as he has never observed a fish in the sto-mach of a Dolphin or Porpoise. He also found, on a visit in May to theso termed island, the water over a large circuit coloured red, owing to thepresence of an Entomostracon, which proved to be Cetochilus. Thus themultitudinous occurrence of the almost invisible Entomostraca is the con-dition of existence of the vast shoals of fish as well as of the gigantic marineMammalia .

Cladocera. —Baird (Ann. Nat. Hist, xi, p. 81), in the continuation ofhis ‘Natural History of the British Entomostraca,’ the progress of which hasbeen interrupted for several years, has subjected the genus Eynceus, Mull.,to a thorough investigation. The generic characters, which have been erro-neously understood by all writers, chiefly require emendation, and the authorthus constitutes them : Rami two, usually very short, branched, each branchthree-jointed. A single eye; in front of which is a black spot; five pairs offeet; intestine convoluted, tail jointed. The author divides the Britishspecies into eight subgenera. (1) Subgenus, Macrothrix; anterior branch ofthe ramus, with a very long seta at the root of the second joint; antennaependulous, from the extremity of the beak : M. latieornis (Monoc. lat., Jur.)(2) Eurycercus: sub-quadrangular, tail very broad, in form of a flat plate,densely serrated: E. lamellatus ( L. lam., Mull.) (3) Chydorus, Leach : almostspherical, beak very long and sharp, curved nearly into a crescent ;rami very short: Ch. sphcericus (L. sph., Mull.) ; and a new species, Ch. glo-bosus. (4) Camptocercus: ovoid, tail long, slender, very flexible, serrated :0. macrourus (L. macr., Mull.). (5) Acroperus: somewhat harp-shaped, ter-minating interiorly on anterior margin in a more or less blunt point projectingforwards; rami rather long: A. harpee (L. harpa, Baird) ; and a new species,A. nanus. (6) Alona: shell quadrangular, striated, rami short: A.quadran-

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