TREMATODES TROM FISHES — LINTON 61 



Subfamily Himasthlinae Odhner, 1911 



Genus HIMASTHLA Dietz, 1909 



HIMASTHLA TENSA, new species 



Plate 4, Figuke 35 



Body nearly linear ; neck short, covered with minute spines, about 

 (J.02 mm. in length and continuing for a short distance back of the 

 ventral sucker; pharynx small, close to oral sucker; esophagus long; 

 intestines begin at anterior border of ventral sucker, indistinct in 

 balsam mounts, but appear to extend to posterior end. Genital pore 

 at anterior edge of ventral sucker on median line; cirrus pouch and 

 seminal vesicle long, extending back of ventral sucker, the seminal 

 vesicle more or less spirally curved; testes longer than broad, near 

 posterior end, one following the other closely. In one of the speci- 

 mens the testes are slightly irregular, the first having a deep notch 

 on one side and the second being constricted about the middle of its 

 length, the posterior half being distinctly narrower than the anterior. 

 Ovary subglobular, a short distance in front of the first testis and a 

 little to the right of the median line. An ample shell gland and vitel- 

 line reservoir lie between the ovary and first testis. The early folds 

 of the uterus contain sperm. The vitellaria extend from the posterior 

 end about to the posterior end of the seminal vesicle. The body is 

 considerably elongated between the ovary and ventral sucker ; numer- 

 ous ova lie along the median line, between the marginal vitellaria, 

 from the ovary to the anterior end of the vitellaria. 



The ventral sucker is larger than the oral, and the mouth is sur- 

 rounded by a single circle of spines, with two extra spines at the 

 angles at each side. These extra spines are posterior to the others, and 

 if continued would form an outer circle. The oral spines are about 

 0.02 mm. in length and 0.015 mm. in breadth; as near as could be 

 determined the number of oral spines is about 32. 



Measurements in balsam: Length, 5.32 mm.; maximum breadth, 

 0.59 mm.; breadth of circle of oral spines, 0.26 mm., of oral sucker, 

 0.11 mm.; pharynx, length, 0.11 mm., breadth, 0.07 mm.; ventral 

 sucker, length, 0.31 mm., breadth, 0.31 mm.; ova somewhat variable, 

 average of four 0.075 by 0.038 mm.; first testis, length, 0.5 mm., 

 breadth, 0.32 mm. ; second testis, length, 0.7 mm., breadth, 0.28 mm. ; 

 distance of second testis from posterior end, 0.7 mm.; length of 

 esophagus, 0.35 mm. 



Host. — Common codfish {Gadus morrhua). 



Record of collections. — Three (U.S.N.M. No. 8214), collected Jan- 

 uary 22, 1915 ; 12 fishes examined. 



