358 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



copiously distributed on both sides of ceca but not covering them dor- 

 sally or ventrally, not extending to edges of body by some distance. 

 Seminal receptacle elongate, along left side of acetabulum. Uterus ex- 

 tending backward in narrow, median coils to level of excretory pore, 

 then forward to metraterm; metraterm large, muscular, overlapping 

 acetabulum. Eggs thin shelled, usually 51 to 56 by 32 to 44 fx, but in one 

 specimen up to 66 /j, in length, and in another as narrow as 26 fi. 



The name scaphoso?nu?n is from scapho (=bowl) and somum ( = 

 body), and refers to the shape of the body. 



Discussion. The specimens collected from Balistes verres are thought 

 to represent the same species, although they are smaller (0.937 to 1.36 

 in length, as compared with 1.552 to 2.268 in the other collections). In 

 them, too, more variation was found in the quantity of vitelline follicles 

 which seemed partly exhausted in some specimens. Some of these speci- 

 mens showed the uterus not reaching the posterior border of the testes, 

 and in one case it was almost wholly anterior to the ovary. However, 

 sucker ratio, egg size, and the internal structure of the cirrus sac agree 

 with material from B. polylepis. 



A consideration of the above species together with the following 

 species leads the writer to conclude that Hypocreadium Ozaki, 1936 

 should be considered a synonym of Pseudocreadium Layman, 1930. 

 Yamaguti (1938) has already shown that Leptocreadium Ozaki, 1936 

 is a synonym of Pseudocreadium. The possible generic distinction be- 

 tween Pseudocreadium and Hypocreadium would be based on the fol- 

 lowing characters of Hypocreadium (which apparently differs in Pseudo- 

 creadium) : smooth cuticula, unlobed ovary, and uterus reaching posterior 

 to the testes. The variable nature of these characters is revealed by ( 1 ) 

 the fact that some specimens of P. scaphosomum show a few spines in the 

 cuticula; (2) the fact that in the following species the ovary may be 

 smooth or considerably lobed; and (3) that in certain specimens of P. 

 scaphosomum the uterus may not reach beyond the testes. 



The following species are known: P. monocanthi Layman, 1930 

 (synonym: Leptocreadium skrjabini Ozaki, 1936); P. vitellosum. 

 (Ozaki, 1936) Yamaguti, 1938; P. symmetrorchis (Ozaki, 1936) n. 

 comb.; P. patellare (Yamaguti, 1938) n. comb.; and the 2 species de- 

 scribed in the present paper. 



P. scaphosomum is most similar to P. patellare. In P. patellare, how- 

 ever, the eggs are larger (63 to 81 by 33 to 43 /a), the ovary smooth, the 

 ceca less undulating, and the prostatic vesicle is undivided and the cirrus 



