132 PROCEEDINGS OF THE NATIONAL MUSEUM voum 



Crassandros, new genus 



Definition: Leptoplanidae of oval form without tentacles; with 

 cerebral and tentacular eye clusters; male apparatus with seminal 

 vesicle and interpolated prostatic mass, not formed into a vesicle; 

 ejaculatory duct surrounded by a heavy musculature; penis papilla 

 wanting; female apparatus typical, with Lang's vesicle. 



Type species: Crassandros dominicanus, new species. 



Crassandros dominicanus, new species 



FiQUKEs 85,b,c; 86,0 



Material: One specimen sent by the U. S. National Museum. 



Form: Oval with broad ends (fig. 85, &) but evidently much con- 

 tracted; 11 mm. long by 8 mm. wide; without tentacles. 



Eyes: Due to the general opacity of the specimen and the presence 

 of heavy folds in the eye region, the eyes were not distinguished with 

 entire satisfaction. What could be seen of them is represented in figure 

 85, c. There is a cluster of tentacular eyes on each side of the anterior 

 part of the brain. The cerebral groups consist of scanty loose eyes 

 behind, in front of, and to the outer side of the tentacular groups. 



Color: This is the usual brown found in preserved polyclads and 

 does not indicate the color in life. 



Digestive tract: The elongate pharynx could be imperfectly 

 seen in the whole animal in a central location with the mouth beneath 

 the posterior part of the pharynx (fig. 85,6). 



CoPULATORY apparatus: Could be seen in the whole animal as 

 three masses behind the pharynx, therefore much posterior in position. 

 These three masses appear to be the prostatic mass, the muscular mass 

 around the ejaculatory duct, and the female apparatus. The copula- 

 tory region was removed and sectioned sagittally. It showed breaks 

 and tears and unfortunately had not been cut sagittally as intended. 

 It is reconstructed in figure 86,a. The spermiducal vesicles approach 

 the anterior end of the male apparatus from behind and form short 

 spermiducal bulbs that join the retort-shaped seminal vesicle, and 

 thus form a tripartite seminal vesicle that has thick muscular walls of 

 mainly circular fibers. It is in continuity, without any intervening 

 duct, with a rounded mass composed of eosinophilous granulations 

 that appears to represent the prostate but is not formed into a definite 

 prostatic vesicle. There seem to be a few muscle fibers among the 

 granulations but the mass is singularly devoid of musculature. The 

 ejaculatory duct from the seminal vesicle was obvious at first but could 

 not be clearly traced through the prostatic mass. The prostatic mass 

 is followed by an elongated area composed almost wholly of circular 

 muscle fibers through which runs a longitudinal duct that is obviously 

 the ejaculatory duct. This duct finally curves ventrally and opens 



