96 PROCEEDINGS OE THE NATIONAL MUSEUM voo. 88 



From common codfish. See Distomum rachion Cobbold, Proc. U. S. 

 Nat. Mils., vol. 20, pp. 538, 539, 1898. 



From haddock: One (U.S.N.M. No. 8287), collected October 31, 

 1895, Vinal N. Edwards collection. Measurements in formalin: 

 Length, 3.43 mm. ; breadth, 0.5 mm. ; diameter of oral sucker, 0.42 mm.. 

 of ventral sucker, 0.3 mm.; pharynx, length, 0.3 mm., breadth, 0.27 

 mm. ; ova, 0.07 by 0.04 mm. 



Three, collected September 3, 1904. 



Six, collected October 21, 1904. Length of largest, in formalin, 

 3.25 mm., breadth, 1 mm.; thickish, appressed, armed with low, flat, 

 rounded spines. Measurements of one in balsam: Length, 1.6 mm.; 

 breadth, 0.63 nun. ; oral sucker, length, 0.21 mm., breadth, 0.22 mm. ; 

 pharynx, length, 0.18 mm., breadth, 0.15 mm.; ventral sucker, length, 

 0.15 mm., breadth, 0.17 mm, ; ova, 0.06 by 0.03 mm. 



The vitellaria in these distomes from the haddock do not extend 

 as far forward as the ventral sucker, and the ovary in some of them 

 is rather more to the right than to the left of the median line. 



One, collected August 12, 1909. This is the only distome found 

 in 16 haddock taken on Crab Ledge, off Nantucket. Length, life, 4 

 mm. Measurements in balsam : Length, 3.5 mm. ; breadth, 0.64 mm. ; 

 diameter of oral sucker, 0.22 mm., of pharynx, 0.18 mm., of ventral 

 sucker, 0.17 mm.; ova, 0.06 by 0.04 mm. Cirrus pouch elliptical, 

 length, 0.18 mm., breadth, 0.14 mm. ; semmal vesicle, relatively large, 

 at posterior border of ventral sucker dorsal to the uterus (fig. 46). 



From silversides: A few cysts, collected August 29, 1908, sur- 

 rounded by black pigment on the skin of a silversides, contained im- 

 mature distomes which agree with this species. Measurements, life: 

 Length, 0.66 mm.; breadth, 0.29 mm.; diameter of oral sucker, 0.12 

 mm., of ventral sucker, 0.08 mm. ; pharynx, length, 0.08 mm., breadth, 

 0.05 mm. Rudiments of the seminal vesicle, ovary, shell-gland, testes, 

 and vitellaria were present, the latter extend forward to the level of 

 the ventral sucker. The prepharynx was as long as the pharynx, 

 and the intestinal rami extended to the posterior end. 



Genus HOMALOMETRON Stafiford, 1904 



HOMALOMETRON PALLIDUM Stafford 



Plate 7, Figures 65-67 



Distomum sp., Linton, Bull. U. S. Fish Comm. for 1899, p. 442, fig. 354, 1901. 

 Homalometron pallidum Stafford, Zool. Anz., vol. 27, p. 487, 1904. — Manter, 

 Illinois Biol. Mon., vol. 10, No. 2, pp. 212, 213, figs. 54-56, 1926. 



Distomes from various species of Woods Hole fishes while differ- 

 ing more or less among themselves, agree in so many essential char- 



