ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 325 



Hhizorhina and Herpyllobius.*— Soren Jensen has mauy criticisms 

 to make on H. J. Hansen's treatment of the two remarkable Copepod 

 parasites, Rhizorliina ampeliscse H. J. H. and Herpyllobius arcticus Stp.- 

 Ltk. He particularly describes the males and the male genital organs. 

 His systematic conclusion is that the family Sphaeronellidas of Giard 

 and Bonnier contains two groups, Choniostoniatinae and Rhizorhininae ; 

 and that Herpyllobius, along with some other slightly known forms, is 

 referable to a quite distinct series, to the family Herpyllobiidse. 



British Amphipods.f — Canon Norman gives lists of the species be- 

 longing to the families Pontoporeudae, Phoxocephalidee, and Ampeli- 

 scidsB; and he also notes the species which have been added to our 

 fauna since the publication of Bate and Westwood's book, by D. Robert- 

 son, T. R. E. Stebbing, A. 0. Walker, J. Hornell, and T. Scott. 



Palaearctic Isopoda4 — Dr. Carl W. Verhoeff, in the course of his 

 •studies on the fauna of European caves, discusses some new or little- 

 known members of this group. In regard to the genus Titanethes, he finds 

 that the only well-known species, T. albus Schiodte, is abundant in the 

 caves of Carniola, while in the caves of Herzegowina it is replaced by 

 T. herzegoivinensis sp. n. The two species are described in much detail. 

 A new sub-family, the Cyphoniscin^:, is erected for two new genera 

 Cyplwniscus and Leucocyphoniscus, each known by a single female spe- 

 cimen only, and occurring, the one in a cave in southern Herzegowina, 

 the other under a stone on Monte Generoso in the Alps. The author 

 also records the finding of new somewhat aberrant species of Armadilli- 

 dium, which necessitates the breaking up of the genus into four sub- 

 genera. 



Annelida. 



Maturation and Fertilisation in Annelida.§ — Edmond Gathy pub- 

 lishes a beautifully illustrated memoir on the development of the egg 

 and the process of fertilisation in Tubifex rivulorum and Clepsine com- , 

 planata. The following are among the more important of the results 

 obtained. In Tubifex the nucleolus of the young ovocyte is rich in 

 nuclein ; but as the egg developes the nucleolus becomes gradually 

 modified, and ultimately yields a nucleolus which gives no colour reac- 

 tion for nuclein. A second nucleolus may appear during development, 

 but if so, it does not arise from the first. The nucleolus gradually dis- 

 solves within the nucleus before or during the formation of the first 

 figure, and it takes no part in the formation of the figure. Polar cor- 

 puscles occur both in the maturation divisions and in the segmentation 

 divisions, and are derived from the nucleus. They are the active agents 

 in the formation of the figures, and determine the appearance of polar 

 spheres and asters. These latter are generally derived from the cyto- 

 plasm, while the spindle arises in whole or in part from the caryoplasm. 

 Asters and polar spheres are not permanent cell-organs, but are mere 

 transitory modifications of the cytoplasm, arising under the influence of 

 the polar corpuscles. The nucleus is reconstructed from vesicles de- 



* Oversigt K. Danske Vidensk. Selskabs Forhandl., 1900, pp. 61-112 (2 pis.)- 



t Ann. Nat. Hist, v. (1900) pp. 826-46. 



\ Zool. Anzeig., xxiii. (1900) pp. 117-30 (11 figs.). 



§ La Cellule, xvii. (1900) pp. 7-62 (-t pis.). 



