NO. 14 MANTER : DIGENETIC TREMATODES OF FISHES 341 



of rhynchus cone shaped, tapering slightly to a fine point which in all 

 three specimens is recurved at its tip to form a hooklike crook. Mouth al- 

 most exactly at midbody; pharynx about 0.075 in diameter; sac-shaped 

 intestine extending forward almost to base of rhynchus. Gonads variable 

 in location. Ovary to the right, slightly anterior to but overlapping phar- 

 ynx; always overlapping and usually entirely dorsal (or ventral) to an- 

 terior testis. Vitellaria in 2 separated lateral groups extending from level 

 of pharynx to base of rhynchus. The 2 groups of follicles converge an- 

 teriorly and almost but not quite meet near base of rhynchus. Total num- 

 ber of follicles about 23. Uterus filling most of body, extending forward 

 beyond anterior limit of vitellaria, overlapping basal portion of rhynchus, 

 posteriorly reaching to level of genital pore. Eggs very large in proportion 

 to body size, 39 to 44 by 20 to 23 [x. 



Testes close together, tandem, diagonal or lateral to each other ; nor- 

 mally probably tandem. Anterior testis overlapping ovary, about at level 

 of pharynx. Both testes wider than long; posterior testis overlapping an- 

 terior edge of cirrus sac. Cirrus sac large, 0.300 to 0.390 by 0.110 to 

 0.136. It may be more than half body length. It contains a coiled tubular 

 seminal vesicle, long pars prostatica, large prostate gland, and has a very 

 thick wall (11 to 12 p.). Genital atrium subspherical, thin walled, with 

 large genital lobes. It is surrounded by a very well-developed mass of 

 gland cells for which the term atrial gland is suggested. Such glands have 

 been described in P. squamatus by Odhner, who compared their appear- 

 ance to that of a shell gland and considered that they secreted the capsule 

 for the spermatophore. Genital pore a short distance in front of the an- 

 terior end, median or to the left. Excretory pore terminal ; excretory ves- 

 icle extending to posterior testis. 



Comparisons. This species is notable for the small body size together 

 with very large egg size. P. costai has even larger eggs but differs in its 

 more elongate body, more posterior uterus, shape and position of testes, 

 and relative size of the cirrus sac. P. rotundus differs from P. aculeatus in 

 its better-developed rhynchus, more anterior mouth, separated vitellaria, 

 and much larger eggs. P. magniovatus Yamaguti, 1938 has eggs almost as 

 large but has a smaller flat rhynchus, confluent vitellaria, and much more 

 posterior mouth. P. scalpellus McFarlane, 1936 is probably most similar 

 but differs in more narrow eggs, more elongate body, more posterior 

 mouth, and more rounded testes. It lacks the hooklike curve at the tip of 

 the rhynchus, and the host is different. Additional material may show, 

 however, that P. rotundus is a synonym of P. scalpellus. 



