ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 723 



lie maintains, originally composed of double-segments, each limb-bearing 

 segment being connected with a preceding segment without limbs more 

 closely than with the succeeding limbless segment. The intermediate 

 segments of insects are degenerate main segments, inherited from Chilo- 

 pod ancestors, and united with the succeeding main segments into 

 secondary double-segments. But we must refer those interested in this 

 intricate question to Verhoeff himself. 



5. Arachnida. 



Development of Telyphonus caudatus.* — W. Schimkewitsch de- 

 scribes the appearance of the embryo of T. caudatus in a series of stages 

 from blastula onwards. On the whole the development exhibits a com- 

 bination of the features characteristic of spiders, particularly Pholcus, 

 and scorpions. There are no important points peculiar to Telyphonus. 



e. Crustacea. 



Death-Feigning in Terrestrial Amphipods.f — F. J. Holmes has 

 studied this phenomenon in Tdorchestia longicornis, Orchestia agilis, &c, 

 in which contact with rigid bodies evokes "a sort of hypnotic effect 

 apparently." The author regards this as the expression of an " instinct " 

 evolved in the course of natural selection ; but no facts are adduced 

 which contradict the view that the phenomenon is a " Reflex-tonus," 

 such as Verworn has described in cases where the possibility of an 

 instinct is out of the question. 



Emergence of Lobster Larvae. J — Fabre-Domergue and E. Bietrix 

 have carefully studied the process of hatching in the common lobster 

 (Homariis). It occurs between 8 p.m. and 9 p.m., and the mother plays 

 a part, moving about as if on tiptoe, and suddenly working the swim- 

 merets so as to jerk out the larvas as soon as they complete the first 

 moult after hatching. 



Habits of Cambarus.§ — J. Arthur Harris discusses some of the 

 chief facts known in regard to the habits and' distribution of North 

 American crayfishes. Different species occur in different parts of the 

 same stream. The burrowing and the " chimney-building " of various 

 species is discussed at some length. The primary use of the burrow 

 seems to be to collect the water in a sort of cistern, so that the crayfish 

 can keep its gills moist when water in the pools is scarce. "Winter- 

 habits, breeding-habits, coloration and the like, are briefly alluded to. 



North American Amphipods.|| — S. J. Holmes contributes a useful 

 synopsis of the Amphipods of the Atlantic coast of North America. 

 The Amphipod fauna of the Pacific coast is still very imperfectly known. 

 The species from the Arctic regions of the American continent are also 

 omitted, except when they range into the region covered. The majority 

 of the known species of eastern North America are, however, repre- 



* Zool. Anzeig., xxvi. No. 707, pp. 665-85. 



t Biol. Bull., iv. (1903) pp. 192-6. See Zool. Centralis., x. (1908) pp. 605-6. 



% Comptes Rendus, cxxxvi. (1903) pp. 1408-9. 



§^Amer. Naturalist, xxx\ ii. (1903) pp. 601-8. || Tom. cit., pp. 267-92. 



