SALPIDA. 



49 



proles solitaria or oozoite, in a number of characters, among the 

 most important of which must be mentioned the presence of 

 generative organs and the absence of a stolon. The salps, as a 

 rule, develop only one ovum (lasis produces several ova and 

 embryos). 



The ovary is in the young form placed in the nucleus by the 

 right side of the intestine and is connected with the epithelium 

 of the atrial cavity by a long stalk, consisting for the most 

 part of a single 

 cord of cells 

 (Fig. 41). The 

 opening of the 

 oviduct will be 

 formed later at 

 the point where 

 the stalk joins 

 the atrial epithe- 

 lium, on the dor- 

 sal side of the 

 atrial cavity, 

 somewhat to the 

 right behind the 

 penultimate muscular ring. Before fertilisation the cord con- 

 necting the ovary to the atrial wall shortens and draws the 

 ovary from the nucleus to the dorsal side. At the same time it 

 acquires a lumen which opens into the atrial cavity. The ovary 

 now has the form of a simple epithelial sac opening into the 

 atrium and containing the ovum. Soon after fertilisation the 

 oviduct loses its opening and the whole epithelial wall both 

 of oviduct and sac constitutes the follicle of the ovum (Fig. 

 42 C, b). 



The testes which develop and ripen after the ovary are a pair 

 of branched tubular glands lying in the nucleus on each side of 

 the digestive organs. They open separately into the atrium. 



Amongst other points of difference between the sexual and 

 asexual form attention may be called to the adhesive papillae 

 on its ventro-lateral surfaces by which the sexual form is attached 

 to its fellows in the chain. There are eight pairs of these. In 

 isolated individuals they disappear. The muscles are less 

 numerous and less developed, and finally the visual apparatus is 



z in E 



FIG. 41. Side view of Salpa democratica-mucronata, sexual 

 form (combined after Claus and Salensky from Korschelt 

 and Heider). cl atrial cavity ; e atrial aperture ; end endo- 

 style ; / peripharyngeal band ; i mouth ; k gill ; n ganglion ; 

 nu nucleus ; od oviduct ; ov ovary ; ph pharynx-cavity ; 

 x aperture of oviduct. 



