432 



ARACHNIDA CHERNETIDEA 



CHAP. 



are eleven in number (except in Chiridium, which has only ten), 



and are frequently bisected by a median dorsal membranous line. 



There are nine ventral plates. There is a membranous interval 



down each side between the dorsal 

 and ventral series of plates. 



The chitinous membrane between 

 the plates is very extensible, render- 

 ing measurements of the body in 

 these animals of little value. In 

 a female full of eggs the dorsal plates 

 may be separated by a considerable 

 interval, while after egg-laying they 

 may actually overlap. The four 

 stigmata are not situated on the 

 plates, but ventro- laterally, at the 

 level of the hinder borders of the 

 first and second abdominal plates. 



The first ventral abdominal plate 

 bears the genital orifice. In the 



FIG. 222. A, Chernes sp., diagram- same plate there are two other orifices, 

 na , ic en ra view, x a * an anterior and a posterior, which 

 ative opening ; p, pedipalp ; i, belong to the " abdominal glands." 



2. 3, 4, legs. (Tiie stigmata are rrii i. i i j.-u 



at the postero-lateral margins of The 7 were taken b 7 Some authors 



the 1st and 2nd abdominal seg- for the spinning organs, but their 



ments. ) B, Tarsus, with claws P . . 111 



and sucking disc. function is probably to supply 



material for the capsule by which 

 the eggs are suspended from the body of the mother (see p. 434). 



The Chernetidea possess chelicerae, pedipalpi, and four pairs 

 of ambulatory legs, all articulated to 

 the cephalothorax. 



The chelicerae are two-jointed, the 

 upper portion of the first joint being 

 produced forward into a claw, curving 

 downward. The second joint is articu- 

 lated beneath the first, and curves 

 upward to a point, the appendage being FlG . 2 23. Cheiicera of <?///,, ,v. 



thus chelate. This second joint, or / Flagellum ; g, galea ; 6-, 

 ,,,..,, ., ., serrula. (After Simon.) 



movable digit, bears, near its extremity, 



the opening of the spinning organ, and is furnished, at all events 



in the Garypinae and Cheliferinae (see p. 437), with a pectinate 



