TREMATODES FROM FISHES — LINTON 93 



this species. They are elongated forms differing from Z. rachion in 

 having a relatively smaller pharynx, and in having both the pre- 

 pharynx and esophagus as long, or longer, than the pharynx. The 

 testes are usually separated from each other by a longer or shorter 

 interval in which follicles of the vitellaria appear. 



Details of structure are given in the records of collections. 



Hosts. — Four-bearded rockling {Enclielyo'pus cimbrius)^ common 

 codfish {Gadus morrhiM), pollack {Pollachius virens)^ summer 

 flounder {Paralichthus dentatus)., codling {Urophycis chuss)^ 

 goggler ( TracMiTO'ps crumenophthalma) . 



Record of coUections. — From four-bearded rockling. Distom/mn 

 sp., Bull. U. S. Fish Comm. for 1899, p. 479, fig. 330, 1901. 



From common codfish : Eight, collected December 21, 1903 ; 24 fishes 

 examined. 



Thirteen, collected December 13, 1905 ; 50 fishes examined. Meas- 

 urements in formalin: Length 1.6 mm., breadth 0,28 mm., nearly 

 linear. One, collected November 12, 1912; 5 fishes examined. One, 

 collected November 15, 1912; 3 fishes examined. Fourteen, collected 

 December 28, 1912 ; 25 fishes examined. Two, collected December 30, 

 1912 ; 15 fishes examined. Measurements of one in formalin : Length 

 2.8 mm., breadth 0.42 mm. ; diameter of oral sucker 0.10, of pharynx 

 0.06, of ventral sucker 0.10; ova, 0.066 by 0.040. Two hundred and 

 thirty-four, collected January 22, 1915; 12 fishes examined. Thirty- 

 seven (U.S.N.M. No. 8284), collected February 16, 1915, from one 

 fish. 



Two, collected July 15, 1926 ; 4 fishes examined. Distomes slightly 

 macerated. These distomes from the cod are slender, neck densely 

 spinose, spines less dense on anterior part of the body, sparse toward 

 the middle of the length, disappearing near the posterior end. Neck 

 when flattened slightly spatulate, broader and thinner than the sub- 

 cylindrical body. The neck is supplied with numerous pyriform 

 glands. Oral sucker a little larger than the ventral sucker, its open- 

 ing directed forward ; pharynx small, longer than broad ; prepharynx, 

 in uncontracted specimens, longer than the pharynx ; esophagus much 

 longer than the pharynx, depending on the degree of contraction, in 

 some cases from twice to more than four times the length of the 

 pharynx. Intestinal rami begin from about the middle to the pos- 

 terior third of the neck and extend to the posterior end of the body. 

 Genital aperture in front of ventral sucker; cirrus bulb oval-ellipti- 

 cal, about twice as long as broad, anterior and dorsal to ventral sucker ; 

 cirrus spinose ; seminal vesicle moderately voluminous, extending back 

 of ventral sucker ; testes two, one following the other, the interval be- 

 tween them approximately equal to the length of a testis, and filled 

 with follicles of the vitellaria. Ovary subglobular, a short distance 



