574 SUMMARY OF CURRENT RESEARCHES RELATING TO 



alimentary canal contains in most cases a green mass, with or without 

 siliceous remains. The food consists of Diatoms and Dinoflagellates, 

 and chiefly of the smaller species. In addition to these the source of 

 the green substance often seen is probably to be found in the extremely 

 minute Protophyta which pass through " Mullergaze No. 20," and occur 

 in great numbers in the sea. Other small organisms, such as Silico- 

 flagellates, occasionally occur. A certain relation seems to exist be- 

 tween the times of maxima of the Copepods in the sea and the maxima 

 of the phytoplankton. It may be that these directly affect one another, 

 or both may be conditioned by other causes at present unknown. 



Summer Resting Stage in Cyclops bicuspidatus.* — E. A. Birge 

 and C. Juday found numerous oval cysts at the bottom of six Wisconsin 

 lakes. Each cyst contained a fully formed but immature Cyclops, which 

 was surrounded by a capsule of cement and detritus with only the 

 abdominal seta? projecting. The Entomostraca emerged in the labora- 

 tory. It is not at present possible to correlate this resting-stage, which 

 lasts for four months or so, till the middle of October, with any physical 

 change in the lake, and it seems only to affect certain individuals of the 

 species. 



Entomostraca from Tripolis and Barka.f — V. Brehm reports on 

 a collection of three Cladocera, three Copepods, and two Ostracods, the 

 interest of which is that they belong to Mediterranean, not to purely 

 African, genera. The Sahara is the faunistic boundary, not the 

 Mediterranean. The Copepods are (1) Cyclops prasinus, mostly con- 

 fined to warm water in the south of Europe ; (2) a variety hyaliaa of 

 C. oithonoides ; and (3) Wolterstorffia conflv.ens, previously known from 

 Holstein. 



Tanganyika Copepods.^ — Gr. 0. Sars reports on a collection made 

 by "W. A. Cunnington, 38 species in all, in the genera Diaptomus, 

 Schizopera, Ilyophilus, Cyclops, Ergasilus, and Ergasiloides g. n. Of 

 these 38 species the great majority, namely, 30, are new to science, 

 and of the genera two have been previously known only from salt or 

 brackish water, viz., Schizopera and Ilyophilus. From Lake Tanganyika 

 29 species were obtained, from Nyasa 11, from Victoria Nyanza only 7. 

 There seem to be no Cladocera in Tanganyika, while in the other two 

 lakes there are several limnetic and bottom forms. Distinct species of 

 Diaptomus occur in the three lakes. Twelve endemic species of Cyclops 

 occur in Tanganyika. 



As to Schizopera and Ilyophilus, Tanganyika has Ilyophilus per- 

 plexus, and seven species of Schizopera ; there is one species of Schizo- 

 pera in Nyasa alone and another in Victoria Nyanza (shared with 

 Tanganyika). Sars does not regard these as "halolimnic" (relict) 

 forms, but as originally derived from "forms accidentally transported by 

 the aid of migratory aquatic birds. Perhaps 7. perplexus has evolved 

 from I. Jiexilis, and the seven Tanganyika species of Schizopera from 

 the type species, *S'. longicauda. 



* Trans. Wisconsin Acad. Sci., xvi. (1908) pp. 1-9. 



t Zool. Jahrb., xxvi. (1908) pp. 439-45 (1 pi.). See also Zool. Zentralbl., xv. 

 (1908) p. 577. J Proc. Zool. Soc, 1909, pp. 31-77 (18 pis.). 



