56 PROCEEDINGS OF THE NATIONAL MUSEUM vol.88 



median border of ovary; ova few; vitellaria from posterior end 

 nearly to ventral sucker, not dense ; intestines extend to posterior end 

 of body. 



Seventy-two (U.S.N.M. No. 8206), collected January 10, 1914, 

 from sea raven ; maximum length, in formalin, 5.5 mm. Body nearly 

 linear; neck tapering, variable, average about 5.5 times in entire 

 length; about 48 oral spines; length of oral spine about 0.05 mm.; 

 spines on neck dense, length about 0.04 mm. ; spines on body smaller, 

 but continue to posterior end; prepharynx, when neck is not con- 

 tracted, longer than pharynx; esophagus lacking; cirrus pouch 

 dorsal to ventral sucker; seminal vesicle extends back of ventral 

 sucker, but not halfway to ovary, more or less crumpled, as if 

 crowded forward by ova ; testes longer than broad, contiguous, or with 

 short interval between; ovary nearly circular in outline, a little to 

 right of median line, near anterior border of first testis. In some 

 there is a short interval between ovary and testis in which follicles 

 of the vitallaria lie. Vitellaria extend from posterior end to ventral 

 sucker, follicles coarse. Testes near posterior end. In one distome, 

 length, 4 mm., the second testis was 0.25 nmi. from the posterior end; 

 in another, length, 4.62 mm., the second testis was 0.35 mm. from the 

 posterior end. Measurements in balsam : Length, 3.15 mm. ; breadth, 

 0.7 mm. ; oral sucker, length, 0.18 mm., breadth, 0.19 mm, ; pharynx, 

 length, 0.25 mm., breadth, 0.14 mm. ; ventral sucker, length, 0.28 mm., 

 breadth, 0.32 mm. ; ova, average of eight, 0.08 by 0.04 mm. 



One (U.S.N.M. No. 8207), collected September 8, 1910, from king- 

 fish. Spines evanescent ; oral spines missing ; a few scattering spines 

 on neck and dorsal side of body. Dimensions in balsam, lateral 

 view : Length, 2.73 nun. ; breadth, 0.56 mm. ; oral sucker, length, 0.14 

 mm., breadth, 0.11 mm.; pharynx, length, 0.21 mm., breadth, 0.15 

 mm.; ventral sucker, length, 0.21 mm., breadth, 0.24 mm.; ova, 0.08 

 by 0.04 mm. Greatest breadth near posterior end at level of pos- 

 terior testis, tapering to anterior end, posterior end bluntly rounded ; 

 prepharynx shorter than pharynx ; esophagus very short or none ; cir- 

 rus pouch long, slender, dorsal to ventral sucker; seminal vesicle 

 long, pyrif orm, behind ventral sucker about halfway to ovary ; testes 

 about as broad as long, separated by a short interval which is filled 

 with vitellaria; posterior testis 0.28 mm. from posterior end; ovary 

 nearly circular in outline, at anterior border of first testis, on right 

 side of median line; vitellaria extend to within about 0.1 mm. of 

 ventral sucker ; vitelline follicles rather coarse ; ova in front of ovary, 

 few. 



Recorded from white perch: Proc. U. S. Nat. Mus., vol. 20, pp. 

 536, 537, 1898; Bull. U. S. Fish Comm. for 1899, p. 456, 1901. One 

 (U.S.N.M. No. 8208), collected May 31, 1907, from white perch; 



