and Laboratory Methods. 1707 



CURRENT ZOOLOGICAL LITERATURE. 



CHARLES A. KOFOID, University of California. 



Books and Separates of Papers on Zoological Subjects should be Sent for Review to Charles A. 

 Kofoid, University of California, Berkeley, California. 



Sars, 0. 0. Contributions to the Knowledge A large part of the material upon which 

 of the Fresh Water Entomostraca of South . ^ ,• i i 



America. I. Cladocera. Arch. f. Math., og. these Studies were made was secured 

 Naturvidenskab, 23 : 1-102, 12 pis. II. from aquaria which had been stocked 

 Copepoda-Ostracoda. Ibid, 24 : 1-152, 8 pis. -^i , • 1 1 1 i • 1 



jgoi. with dried mud and dried aquatic vege- 



tation from Brazil and Argentina. 

 Aquaria thus stocked and provided with the proper amount of aquatic vegetation 

 produced a succession of C/adocera throughout the season. Aquatic plants intro- 

 duced into such aquaria should be carefully freed from all mud, and washed in 

 filtered water to prevent contamination with indigenous species. Confinement 

 in aquaria seemed not to interfere with the usual cycle of parthenogenetic and 

 sexual generations ; for example, the males of Diaphanosoma, Simocephalus, Mac- 

 ro/hrix, Leydigiopsis, A/onelia, Chydonis, and Euryalona were found in such aquaria. 

 It is thus possible to secure in many cases the two sexes, and both partheno- 

 genetic and ephippial ova, as well as the immature and adult stages. This 

 method offers the further advantage of affording opportunity for the study of the 

 habits of the living C/adocefa. Dried mud from the bottom of aquaria may be 

 kept for stocking new aquaria in subsequent years. Among the Copepoda, the 

 Centropagidce alone can be reared by this method. The CycIopidcB and Harpacti- 

 cidce seem not to form the resistant ova which survive the drying process. The 

 method here described is a valuable one, not only for the study of the Entomo- 

 straca of distant lands, but may also be utilized with profit in the laboratory study 

 of our native species, since it offers a ready means of control of the supply of 

 living forms both as to time and numbers. It can be used with equal profit in 

 the study of other fresh water organisms used in laboratories of instruction, such 

 for example as Amoeba, Paramoecium, Stentor, Vorticella, the rotifers, and fresh 

 water nematodes. A stock once started may be kept from year to year by 

 allowing the aquarium to dry up slowly and keeping the dried bottom deposit for 

 seeding new aquaria. c. a. k. 



Wallengren Hans. Ueber das Vorkommen intestinal glands opening into the 

 und die Verbreitung der sogenannten In- ° r o 



testinaldrusen bei den Decapoden. Zeitschr. digestive tract (oesophagus and hind 



f. wiss. Zool. 70: 321-345. 12 figs., 1901. gy^^) jnay be demonstrated in Crustac.a, 



such as the crayfish and lobster, as follows : The digestive tract is dissected out, 

 cut open and stretched out upon a wax plate, washed for ten minutes in distilled 

 water, then placed for ten minutes in the dark in a 0.25 per cent, solution of 

 silver nitrate. In about this time it becomes white and opaque, and should be 

 removed to distilled water, in which it is washed for several hours. It is then 

 brought into the sunlight. As soon as the surface becomes slightly browned the 

 tissue is transferred to glycerin for final examination. The openings of the 



