VERMES GENITAL ORGANS 



263 



masses between the branches of the intestine, especially on the dorsal 

 side. These masses of eggs are regarded as ovaries. It is, however, 

 possible /that they consist of eggs which have left the real ovaria. 



genital 



FIG. 176. Section through Myzostoma, after v. Graff, ov, Ovaries ; da, intestinal branches ; 

 u, uterus ; dm, dorso-ventral muscle fibres ; sn, suckers ; li, testes ; qm, transverse muscles ; l>m, 

 ventral ganglionic masses ; pa, parenchyma ; md, intestine. 



The origin and places of formation of the eggs are not known with any 

 certainty. The ripe eggs pass into a spacious uterus which lies on the 

 dorsal side of the stomach -intestine. One dorsal and two lateral 

 oviducts connect the uterus with the cloaca. The male 

 apparatus is paired. On each side 

 branched solid testicle strands 

 lie in the parenchyma below the 

 intestine and its branchings. On 

 each side an anterior and a pos- 

 terior vas deferens collect the 

 sperm from the testes. Both 

 vasa deferentia enter a muscular 

 lateral sperm vesicle, which lies 

 between the 3d and 4th suckers, 

 and which opens outwardly at the 

 edge of the body. 



Prosopygia. The places of 

 formation for the eggs and sperma- 

 tozoa of the Sipunculidce, Phoron- 



idee, and Bracliiopoda are definite 

 points of the endothelium of the 

 body cavity. The sexual products 



fall into the coelomic fluid, and 



. , , , ,1 FIG. 177. Diagrammatic representation of 



are emptied OUt thence by the the organisation of a Brachiopod, from the dor- 



nephridia, as Was the Case in the sal side ; the dorsal halves of shell and mantle are 



Polychseta. 



removed, a, Arms ; mh, mantle cavity ; m, mouth ; 

 I, liver ; ma, stomach ; n, nephridia ; an, anus ; 

 In the Sipunculidce the formation of 9, genital glands ; vs, part of the ventral shell 



the germs takes place for the most part whic ? proje( ; ts ^ ckwards over the dorsal shell; 



, , v, anterior ; h, posterior ; r, right ; I, left, 



at the base of the ventral proboscis 



retractors. Phoronis is hermaphrodite. The male and female sexual products arise 



