436 



ARANETNA. 



pairs of appendages (shewn as small knobs at ab) appear behind the ambu- 

 latory feet. The abdomen is bent forwards so as to reach almost to the 

 pedipalpi. In the later stages (fig. 198 C) the adult form is gradually 

 attained. The enormous upper lip persists for some time, but subsequently 

 atrophies and is replaced by a normal labrum. The appendages behind the 



FIG. 197. SEGMENTATION AND FORMATION OF THE BLASTODERM IN CHELIFER. 



(After Metschnikoff.) 



In A the ovum is divided into a number of separate segments. In B a number of 

 small cells have appeared (bl) which form a blastoderm enveloping the large yolk 

 spheres. In C the blastoderm has become divided into two layers. 



ambulatory feet atrophy, and the tail is gradually bent back into its final 

 position. The segmentation and the gradual growth of the limbs do not call 

 for special description, and the formation of the organs, so far as is known, 

 agrees with other types. 



The segmentation of Chthonius is apparently similar to that of Chelifer 

 (Stecker, No. 437). 



Phalangidae. Our knowledge of the development of Phalangium is 

 unfortunately confined to the later stages (Balbiani, No. 438). These stages 

 do not appear however to differ very greatly from those of true Spiders. 



Araneina. The eggs of true Spiders are either deposited in 

 nests made specially for them, or are carried about by the 

 females. Species belonging to a considerable number of genera, 

 viz. Pholcus, Epeira, Lycosa, Clubione, Tegenaria and Agelena 



