TREMj^TODES from fishes — LINTON 15 



Family HEXASTOMATIDAE Price, 1936 

 Genus HEXOSTOMA Rafinesque, 1815 



HEXOSTOMA THYNNI (De la Roche) 



Hewacotyle thynni (De la Roche), Linton, Bull. U. S. Fish Comm. for 1899, p. 

 446, figs. 296-298, 1901. 



Record is here made of one specimen of this species, collected Au- 

 gust 21, 1900, by Dr. C. B. Wilson from the mouth of the bonito 

 {/Sarda sarda) . 



Dimensions in life: Length 5 mm., breadth 1.5 mm. Color faint 

 red. When compressed under cover glass a mass of globular bodies 

 of different sizes was extruded from the excretory pore. 



Family MAZOCRAEIDAE Price, 1936 

 Genus MAZOCRAEOIDES Price, 1936 



MAZOCRAEOIDES GEORGEI Price, 1936 



Plate 16, FiGimEs 202-209 



Masocraeoides georgei Price, George Washington Univ. BuU. (Summaries of 

 Doctoral Theses, 1934-36), p. 13, 1936. 



Body, at rest and in preserved material, lanceolate; in life, capable 

 of great alterations of length and breadth, usually slightly pointed 

 in front of anterior suckers. Posterior third of body, more or less, 

 with four suckers on each side; suckers with chitinous frames, and 

 pedicels, which are very flexible in life, extending to a length nearly 

 equal to half the breadth of the body and contracting until the 

 chitinous portion is immersed in the substance of the body. In 

 preserved material the pedicels of the posterior suckers are short. 

 There is a cluster of six hooks at the posterior end, one larger pair, 

 and two smaller pairs between the larger. Pharynx elliptical, longer 

 than broad, near anterior suckers; esophagus as long as or longer 

 than pharynx ; rami of intestine much branched, but concealed by the 

 vitellaria; genital sucker armed with short, recurved spines, a short 

 distance back of forking of intestine. The single testis is in the 

 posterior third, on the left side of the median line, and is deeply 

 lobed on the lateral margin. The ovary, including germ-containing 

 portion, lies on the right side of the median line parallel with the 

 testis, extending a little farther anteriorly than the testis, but not 

 quite so far posteriorly. The anterior portion, the ovary proper, 

 is compact, the posterior, more elongated portion contains large, 

 nucleated germ cells. The vitellaria are very voluminous and extend 

 in broad lateral masses from a short distance behind the genital 



