of the Ova 0/ Chtlionius. 



199 



of the ovary is pushed outwards in the form of a round emi- 

 nence, giving rise to the peculiar racemose form of the ovary. 

 As the development of the ova advances, the wall of the ovary 

 is pushed still more outwards, so that then each ovum is 

 enclosed in a perfectly homogeneous follicle * (therefore with- 

 out any epithelial layer) , the basal section of which appears 

 in the form of a short pedicle lined with nucleated cells 

 arranged in a spindle-like form. 



■pd 



^ / ^9 4/ 



u m 



Embryoual development in Chthonius, represented in seven successive 

 stao-es : 6/,, blastoderm (first layer) ; Wg* mesodermic pells (?) ; /, 

 follicle ; (j, coarser granules of the protoplasm ; k, Purkinje's vesicle ; 

 kh, vitelline membrane ; p, protoplasm ; j)d, primary deutoplasm- 

 spheres; S7n, secondary membrane; sd, secondary deutoplasm- spheres 

 (nutritive vitellus). 



The ovum is now developed chiefly by a rapid increase of 

 volume of the protoplasm, in which we must distinguish two 

 kinds of granules, coarser and finer. The coarser granules 



* Von Wittich, ' Observationes qusedam de Aranearum ex ovo evolu- 

 tione,' Diss, inaug. Halis Saxonise, 1845; and id. "Die Entstehung des 

 Arachnideneies im Eierstock, die ersten Vorgange in demselben nach 

 seinera Verlassen des Mutterkorpers," Miiller's Arch, fiir Anat. und 

 Physiol. 1849, pp. 112-150, pi. iii. (see p. 1 16). 



14* 



