482 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 89 



Genus ENANTIA GraflF, 1890 

 Defmition. — With the characters of the family, 



ENANTIA PELLUCIDA (Pcarse, 1938), new combination 



Figure 31, o, & 

 Acerotisa pellucida Pel^bsb, 1938, p. 90, fig. 33. 



Material. — Two whole mounts in Pearse collection labeled Acero- 

 tisa pelliocida^ one the type ; other cut into sagittal serial sections. 



Form. — Oval, flat, thin, delicate (see Pearse, 1938, fig. 33) ; size of 

 preserved specimens given in Pearse as 7.1 by 4.3 mm. and 5.7 by 3.8 

 mm. No tentacles; no sucker. Margin, except anterior end, with 

 yellow cuticular spines ; in the remaining whole mount only three such 

 spines can be seen, close together near the posterior end on one side; 

 presumably the others have been lost. In the set of sections, about 40 

 such spines appear to have been present. Evidently E. pellucida has 

 fewer marginal spines than E. spinifera. As Graff (1890) has fully 

 described and illustrated the structure of these spines, an account of 

 them here appears superfluous. 



Eyes. — Pearse's figure and description erroneous; no marginal eyes; 

 eyes small, in usual tentacular and cerebral groups (fig. 30, a, same 

 specimen as Pearse's figure 33). Tentacular groups of about eight 

 eyes, cerebral groups scattered, of about 10 eyes, extending forward 

 from brain ; on each side there is an eye behind each tentacular cluster. 



Color. — Pale, whitish, pellucid. 



Digestive tract. — Pharynx (fig. 30, «) short, tubular, directed for- 

 ward, in anterior body fifth; from this main intestinal trunk ex- 

 tends posteriorly in median line, giving off a few^ large branches, 

 which branch and anastomose. 



Reproductive system. — Very similar to that of E. spinifera. Male 

 complex immediately- behind pharynx; male canal leads dorsally 

 from male genital pore into pyriform mass, marked off from paren- 

 chyma by a muscle layer. This mass contains in its anterodorsal 

 part the seminal vesicle, which has a muscular wall and receives 

 from below separately the two vasa deferentia (fig. 30, h). Semi- 

 nal vesicle discharges into a cavity containing the introverted penis 

 papilla. The male S3'stem of E. pellucida thus differs from that of 

 E. spinifera chiefly in that in the latter the penis is protruded, in 

 the former introverted, probably merely a functional difference. 

 Prostate appears entirely wanting. 



Female genital pore shortly behind male pore (fig. 31, 6) ; leads 

 into long vagina, which extends posteriorly in median line, has a 

 kink w^here the shell glands enter, posterior to this receives a pair 

 of uteri, and then continues as an elongated Lang's vesicle (fig. 31, «, 



