NEMATHELMINTHES 



rl -9 



retinaculum ; in the male they are in connexion with a special 

 genital ganglion which lies near the ductus ejaculatorius. 



With the exception of certain 

 sensory papillae in the neighbour- 

 hood of the male genital orifice, and 

 of three similar papillae mentioned 

 by Kaiser on the proboscis, the 

 Acanthocephala are devoid of sense 

 organs. 



The Acanthocephala are dioecious ; 

 their generative organs are developed 

 in connexion with the ligament, 

 a cord-Like structure which arises 

 between the inner and outer layer 

 of the hinder end of the proboscis 

 sheath and traverses the body-cavity, 

 ending posteriorly in connexion with 

 the genital ducts. The testes lie 

 in this ligament; they are paired 

 oval bodies which open each into a 

 vas deferens. The vasa deferentia 

 each bear three lateral diverticula, 

 the vesiculae seminales ; and three 

 pairs of cement glands pour their 

 secretion into a duct which opens 

 into the vasa deferentia ; the latter 

 unite and open by a penis which 

 is withdrawn into a genital bursa, 



Zed. (From Hamann.) a, Probo- The two ovaries are formed in 

 $CSS*tSS3 the ligament of the female in a cor- 



ganglion ; /, /, retractors of the responding position to that occupied 

 proboscis sheath ; ff, g, lenmisci, , , , , i i , 



each with two giant nuclei ; h, l>y the testes in the male, but at an 

 space iu sub-cuticuiar layer of early stage they break down into 



the skin ; I, ligament ; m, w, * . - , , ,., /. 



testes ; o, glands on vas deferens ; packets of Cells, of which tllOSC of 



p, giant nucleus in skin ; q, open- ^ e peripheral layer develop into ova 



ing of vas deferens. * 



at the cost ot the central cells, which 



serve them as a food supply. As these masses grow and 

 increase in number they rupture the walls of the ligament, and 

 escape into the body-cavity, in which they float. The ova are 



