114 RITTER 



vientioned part, and coextensive "with the esophagus, with which it 

 is conitected. Collar funnels of the usual form, though very short; 

 directed outward at nearly a right angle to the long axis of the body, 

 instead of forward ; opening into the first gill pouch. (PL VII, figs. 

 3, 4, and 7.) 



Pharyngeo-genital region. — Separation of the eiiteric wall into 

 pharyngeal and esophageal portions by deep longitudinal folds on 

 each side. At the anterior end the pharynx occupies but little more 

 than the dorsal half of the wall, while posteriorly the esophageal por- 

 tion becomes much reduced. No synapticulae in branchial bars. 

 Epibranchial ridge very prominent. Male gonads both extra- and in- 

 ter-branchial, the extra-branchial far more voluminous, in the form of 

 large, more or less globular lobes, the extra-branchial lobes much 

 larger than the inter-branchial ones. Female gonads apparently extra- 

 branchial only. Gonads retained in the body cavity, and not raised 

 up into genital pleurse to overarch the branchial orifices. 



Abdo7ninal region. — No external liver lobes, but a single pair of 

 broad laminar appendages attached to the dorsal side of the intestine 

 immediately behind the pharynx, and for some distance in this region 

 the intestinal wall much thickened, and the lumen correspondingly 

 reduced in size as compared with the portions farther back. No in- 

 testino-cutaneous pores. Ventral longitudinal muscle layer broad and 

 but little thicker than the same layer in the dorsal and lateral regions. 

 No circular muscle layer in this portion of the body. 



The trunk coelom narrows off on each side anteriorly and terminates 

 immediately behind the posterior limit of the collar. The structure- 

 less membrane lining the cavity becomes thickened and dense in this 

 narrowed anterior end, and at the extreme tip there is a patch of this 

 membrane on which is situated some peculiar epitheloid cells. These 

 are high and slender, sometimes tailed, and ai'e set on both sides of the 

 membrane, perpendicular to it, and close together. In some individuals 

 this patch is thrust forward and outward in its middle so as to produce 

 a definite though short and narrow pouch, into which the epitheloid 

 cells of the inner surface project so as to divide the cavity of the pouch 

 into narrow spaces. 



This peculiar structure seems to be 2:)resent in every specimen, but 

 varies considerably in form and definiteness. It is usually in close re- 

 lation to the collar funnels, though there seems to be no connection 

 between them. I am unable to find anything comparable to them in 

 any other species. The most plausible suggestion that I can make 

 about them at present is that they may represent the peripharyngeal 



