Miscellaneous. 429 



think that in the Araneida production by virgin females takes place, 

 and that fecundation by the males is unnecessary, at least under all 

 circumstances. But to get at the knowledge of the t?ruth, it is often 

 very useful not to rest satisfied with a single set of observations. The 

 examination of the generative organs of the Araneida in fact gives 

 the most complete explanation of these productions by females kept in 

 captivity for several years. 



x\mongst the Araneida we must distinguish between those whose 

 life only lasts one season, and those of which, on the contrary, the 

 existence is prolonged far be3'ond this term. In the former a single 

 oviposition takes place ; in the others, the broods succeed each other 

 from year to year without the concourse of the males ; only, as is 

 "shown by attentive observation and experiment, the concourse of the 

 male is necessary at least once. 



Mygale, Clotho, Filistata, Segestria, &c., all belong to the cate- 

 gory of species which usually live several years ; in all, leaving out 

 of consideration certain secondary modifications, the female apparatus 

 is composed of two large tubes, sometimes united at the extremity, 

 sometimes isolated and terminated by a caecum, to which the ovarian 

 chambers are appended. At the moment of copulation these tubes 

 receive the seminal fluid in abundance ; they are true spermatic reser- 

 voirs ; the eggs, on the point of being expelled, are impregnated 

 during their passage. The fecundating liquid not being exhausted by 

 a single oviposition, and being preserved with all its qualities in its 

 reservoirs, as 1 have repeatedly ascertained by microscopic examina- 

 tion, new ovipositions may take place at longer or shorter intervals, 

 without any necessity for fresh copulations. 



Tiie study of the arrangement of the generative organs, and the 

 ascertainment of the presence of spermatozoids in the large ovarian 

 conduits, prove convincingly that the female Araneida are not fitted 

 to furnish fertile products, except after copulation. But this kind of 

 proof is not the only one to which I have turned my attention. 

 Keeping in captivity spiders of different kinds, especially of the 

 genera Mygale and Filistata, which had not acquired their full 

 development, I have succeeded, in many cases, in feeding them up to 

 the term of their growth ; these individuals, taken young, had cer- 

 tainly never received the approaches of the male, and the eggs ob- 

 tained from them always remained barren. — Comptes Rendus, 6 April 

 1857, p. 741. 



On the Brain of the Dytici, in its relations to Locomotion. 

 By E. Faivre. 



The following experiments have been made upon a great number 

 of Bytici, both males and females, with the view of ascertaining the 

 relations of tlie cerebral ganglia to the locomotion of the animals. 



1. Total or partial removal of the supra-cesophageal ganglion. — 

 If the whole of the supra-oesophageal ganglion be removed from a 

 Dyticus, the animal remains motionless for some moments, without 

 giving any signs of great pain. It soon begins to walk straight for- 

 ward, but with much greater difficulty than in the normal state ; it 



