344 FUNAFUTI ATOLL. 



Behind the intestinal diverticulum of the anterior portion of 

 the genital region, the genital cushions gradually become more 

 prominent until about the middle of the genital region proper 

 they form marked thick lateral projections (fig. 12, gnc.) into 

 which the dorso-lateral portions of the gut pass. Posteriorly the 

 genital cushions gradually fade away as the hepatic region is 

 approached. 



The coelom in the genital region is completely divided into two 

 lateral halves, above by the high dorsal mesentery, and below by 

 the ventral vessel. The dorsal vessel (fig. 12, dv.) occupies only 

 a small portion of the dorsal half of the dorsal mesentery. The 

 lateral septa have the usual relations : they extend into the 

 posterior portion of the branchial region. 



Gonads. In the branchial region, gonads exist only laterally 

 to the gill pores. They are much branched sacs, occupying in 

 mature individuals the greater part of the coelom in that region. 

 In P. minuta and P, sarniensis, according to Spengel, the gonads 

 in the branchial region are simple unbranched sacs. The genital 

 pores open in the submedian lines close to the base of the lateral 

 wall of each branchial groove. Towards the hinder end of the 

 branchial region, the submedian lines shift upwards, so that the 

 genital pores on each side open into the branchial groove about 

 the middle of its lateral wall. Posteriorly the submedian lines 

 pass still more dorsally, and, in the genital region proper, the 

 genital pores open close to the free margin of the genital cushions 

 on their mesial sides (tig. 12, 



In the genital region the gonads consist each of two main sub- 

 divisions (1) a lateral division situated on the outer side of the 

 lateral septum (fig. 12, git.) and (2) a mesial division situated on 

 the inner side of the septum and extending mesially towards the 

 dorsal mesentery (fig. 12, gm.). Both these main subdivisions are 

 again irregularly branched. 



Post-genital Region. The hepatic region in its general features 

 corresponds with that of P. minuta. The intestinal and hepatic 

 epithelial cells contain numbers of greenish granules. 



The hind body calls for no detailed consideration. The two 

 ciliated grooves of the intestine are related essentially as in P. 

 australiensis . The intestine is provided with a long and high 

 keel-like process, the slightly enlarged ventral edge of which over- 

 lies the minute ventral vessel. The dorsal and ventral vessels, 

 the keel-like process of the intestine, and the dorsal nerve disappear 

 shortly in front of the posterior end of the body. The ventral 

 nerve can be traced to the extreme posterior end. The radial 

 fibres passing between the limiting membrane of the epidermis 

 and that of the intestine are well developed. 



