324 ARACHNIDES. 



sacs, and then of a second stomach or dilatation surrounded with 

 silk. 



The nervous system is composed of a double cord occupying the 

 median line of the body, and of ganglions which distribute nerves to 

 the various organs. 



With respect to the simple eyes, or ocelli, Mr Dafour remarks 

 that they shine in darkness like those of Cats, and that the Araneides 

 most probably enjoy the faculty both of nocturnal and diurnal 

 vision. 



The abdomen becomes so putrid and decomposed after death, 

 that its colours and even its form are soon destroyed. M. Dufour, 

 by means of a rapid desiccation, the mode of which he points out, 

 has succeeded in remedying this evil to a great degree. 



The silk, according to Reaumur, is first elaborated in two little 

 reservoirs, shaped like tears of glass, placed obliquely, one on each 

 side, at the base of six other reservoirs, resembling intestines, situated 

 close to each other, flexed six or seven times, proceeding from a 

 little beneath the origin of the abdomen, and terminating in the pa- 

 pillae by a very slender thread. It is in these last mentioned vessels 

 that the silk acquires a greater degree of firmness and other proper- 

 ties peculiar to it; they communicate with the preceding ones by 

 branches, forming a number of geniculate turns, and then various 

 pieces of net-work. The newly spun filaments, when first drawn 

 from the mamillas, are adhesive, and a certain degree of desiccation 

 or evaporation is required to fit them for their destined purposes. 

 When the temperature is propitious, however, a single instant is 

 sufficient, as the animal employs them the moment they escape from 

 the apparatus. Those white and silky flocculi that may be observed 

 floating about in spring and autumn in foggy weather, are certainly 

 produced as we satisfactorily ascertained by tracing them to their 

 point of origin by various young Araneides; they are mostly the 

 larger threads which are intended to afford points of attachment to 

 the radii of the web, or those that compose the chain, and which, 

 becoming more ponderous by the access of moisture, sink, approach 

 one another, and finally form little pellets: we frequently observe 

 them collected near the web commenced by the Spider, and in 

 which it resides. 



It is also very probable that many of the young animals, not hav- 

 ing as yet a sufficient supply of silk, limit their structure to throwing 



