ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 309 



sexes are produced from the proportion of the sexes at later stages of 

 growth. It further points at a possible connection between sexual 

 dimorphism and a different sexual mortality rate. But until more cases 

 of a similar nature have been investigated, it would be unprofitable to 

 dwell on this point. 



Sex Recognition among Amphipods.* — S. J. Holmes has deter- 

 mined experimentally that neither sight nor smell are probable factors 

 in enabling the males of HyaMla to recognise the females. It appears 

 that accidental contact in their random movements is the initial factor 

 which effects the union of the sexes. The male has a strong instinct 

 to seize and carry other individuals of the same species, while the female 

 tends to lie passive when touched, and especially so if she is seized. 

 Mutilated males, which could not resist, were carried about for hours 

 by other males, but dead specimens of either sex were not so carried. 



New Hyperiid Amphipod.f— A. Senna describes a remarkable new 

 genus, Thaumonectes, from the Caraibic Sea, which must be placed near 

 Thaumatops, among the Hyperiid Amphipods. 



Holopedidae.J — Th. Stingelin discusses this divergent family of 

 Cladocera, in which the second antenna} are uniramose. In addition to 

 Holopedium gibberum Zaddach, which occurs in North Europe and North 

 America, he describes H. amazonicum sp. n., from the mouth of the 

 Amazon. He gives a revised diagnosis of the genus and the family. 



Winter Eggs in Copepods.§— E. Wolf has proved the existence of 

 winter eggs in two species of Diaptomus, viz. D. cceruleus and D. castor. 

 He found, e.g. D. cceruleus in muddy holes containing stagnant water in 

 August, which remained dry through the winter. In April of the fol- 

 lowing year he moistened a small part of the mud, and in two days 

 nauplii were to be seen, whose development was followed till their 

 Diaptumus nature was quite clear. Subsequently, he found the eggs in 

 the mud, enclosed within a double envelope. 



Annulata. 



Cephalisation and Metamerism in Annelids. || — ■ A. Malaquin has 

 studied this problem with especial reference to Tomopteris, and comes 

 to the following conclusions. The cephalic segment of Annelids had 

 primitively a locomotor function, like the trunk segments, but this has 

 given place to more specialised sensorial functions. The cephalic seg- 

 ment may bear true setigerous outgrowths, homologous with parapodia. 

 Cephalisation has been effected in Annelids by the transformation of a 

 single metamere bearing the buccal orifice. 



Nematode in Smooth Muscle-Cells of Nephelis.f— A. Schuberg 



* Biol. Bull., v. (1903) pp. 288-92. 



t Bull. Soc. Entomol. Ital., xxxv. (1903) pp. 93-o (1 fig.). 



j Revue Suisse Zool.. xii. (1904) pp. 53-64 (1 pi.). 



§ Zool. Anzeig., xxvii. (1904) pp. 98-108. 



|| Comptes Rendus, cxxxviii. (1904) pp. 821-4. 



•j Zeitschr. wiss. Zool., lxxvi. (1904) pp. 509-21 (1 pi.). 



