330 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



Discussion. — The three specimens collected agree with most of 

 the important specific characters of S. dentatum, such as : contin- 

 uous distribution of vitellaria to the acetabulum, 48 to 50 oral 

 spines, and contiguous gonads. The forebody is extended, and the 

 prepharynx is about twice the length of the pharynx or longer 

 than in most specimens of dentatum. Sucker ratios are 1:1.33; 

 1:1.37 and 1:1.625 or slightly above the ratio (1:1.22) described 

 for dentatum. Eggs are 61 to 68;a by 42 to 50;a. These measure- 

 ments approach or reach those given for S. pagrosomi (Yamaguti, 

 1939), which Manter (1947, p. 308) pointed out was very similar 

 to S. dentatum. It is here considered a synonym. 



Genus PLEORCHIS Railliet, 1896 



PLEORCHIS CALIFORNIENSIS, new species 



Plate 13, Figure 14 



Description (based on two mature and five immature speci- 

 mens. Measurements given are for the mature specimens).— 

 Length 4.901 to 6.435 mm. ; width 1.495 to 2.058 mm. ; a specimen 

 3.536 mm. long is immature. Oral sucker 0.365 to 0.400 mm. in 

 transverse diameter, somewhat wider than long ; acetabulum cir- 

 cular, 0.292 mm. in diameter ; sucker ratio 1 :0.73 to 0.8. Forebody 

 0.766 to 1.261 mm. or about one-fifth to one-sixth body length. 

 Anterior half of body with large conspicuous spines. A pair of 

 small, rather widely separated eye spots on the dorsal surface 

 at, or slightly posterior to, posterior edge of oral sucker. In the 

 holotype (largest) specimen, the eye spots show signs of being 

 lost and the one on the left has disappeared although very fine 

 black granules occur at its location. Prepharynx 0.043 to 0.243 

 mm. long, varying with contraction of the forebody; when ex- 

 tended it is almost as long as the pharynx ; pharynx 0.215 by 0.241 

 mm. long by 0.219 to 0.234 mm. wide; esophagus a very short nar- 

 row tube only 0.021 to 0.029 mm. long; ceca with anteriorly di- 

 rected arms 0.343 to 0.438 mm. long (ace, pi. 13, fig. 14), and 

 with short lateral branches (ca) arising from outer (or lateral) 

 edges beginning shortly posterior to acetabulum ; ceca ending near 

 posterior end of body. Testes in dorsoventral pairs arranged in 

 two longitudinal rows, usually 26 or 27 pairs in each row to total 

 104 to 108 testes ; smallest number observed was 21 and 25 pairs or 

 92 testes. Testes wider than long, close together in the rows. Cirrus 

 sac thin walled, containing a large, ovoid seminal vesicle, more or 

 less clearly divided into a narrowing anterior portion curving 

 around the acetabulum and a saclike posterior portion (sv) ; ex- 

 tending well posterior to acetabulum to near the ovary ; prostatic 

 cells few; cirrus tubular, unspined. Ovary lobed with short, thick 



