NO. 14 manter: digenetic treiniatodes of fishes 443 



The excretory system is peculiar in the backward direction of the 

 collecting tubes which then coil forward, giving off some branches. The 

 peculiar circumferential ring around the anterior edge of the oral sucker 

 is clearly evident as are the short coiled, blunt branches it gives off. 



The uterus is remarkably developed and obscures almost all other 

 organs. It is surprising to find such a small ovary producing so many 

 thousands of eggs. 



Aporocotylidae Odhner, 1912 



Psettarium tropicum, new species 

 (PlateSO, figs. 134-136) 



Host: Cheilichthys annulatus (Jenyns) 



Location: Recovered from washings of the coelom and once 

 from the intestine. Probably originally in the blood 

 vessels 



Locality: San Francisco, Ecuador 



Number : 3 specimens, 2 incomplete, from a single host 



SPECIFIC DIAGNOSIS OF PSETTARIUM TROPICUM 



Body flat, thin, elongate, spined, 3.483 in length by 0.412 in greatest 

 width, tapering slightly toward each end, almost equally wide along 

 most of body length. Spines along edge and extending inward dorsally 

 or ventrally a short distance; near anterior end spines in short trans- 

 verse rows, lateral and partly dorsal, each row containing about 12 

 small pointed spines which tend to fuse at edge of body to form a 

 narrow blade. Posteriorly, the rows of spines become single bladelike 

 spines. Not far from posterior end, the rows may extend onto ventral 

 surface and again be composed of small, separated spines as in anterior 

 region. Right unilateral lobe about 0.3 long at posterior end of body. 

 Suckers lacking. Mouth terminal; esophagus 0.877 long or about %. 

 body length, slightly sinuous ; glandular cells around base of esophagus ; 

 anterior ceca about 0.112 long; posterior ceca about 1.728 long; about 

 0.9 or slightly over %. body length is posterior to intestinal ceca. 



Testes diffuse, indistinct, with boundaries too indefinite to allow 

 counting; small, irregular mass of testicular tissue (almost indistinguish- 

 able from vitellaria) in median, intercecal region of body. (Such indis- 

 tinct testes seem to occur in related forms such as Psettarium japonicum.) 

 Vas deferens slightly sinuous, becoming opposite posterior indentation of 

 body a simple elongate seminal vesicle (fig. 135); cirrus sac weakly 



