90 PROCEEDINGS OF THE NATIONAL MUSEUM vol.88 



small, oval-elliptical distomes, varying from a length of 0.22 mm. 

 with a breadth of 0.15 mm., to length 0.45 mm., with a breadth of 

 0.28 mm.; minutely and densely spinose at anterior end, spines be- 

 coming sparse toward posterior end; oral sucker larger and more 

 muscular than ventral ; pharynx about as broad as long, much smaller 

 than oral sucker; prepharynx and esophagus very short; intestines 

 reach to posterior end; cirrus and cirrus-pouch dorsal to ventral 

 sucker, seminal vesicle extending back of ventral sucker; genital 

 pore at anterior edge of ventral sucker, a little to left of median line ; 

 testes diagonal, nearly transverse in one, about midway between 

 ventral sucker and posterior end; ovary to right of median line in 

 front of right testis; yolk reservoir between ovary and right testis, 

 best seen in dorsal view; shell gland ventral to left side of yolk 

 reservoir, extending to median line; seminal receptacle dorsal to 

 anterior border of left testis; a second seminal vesicle was faintly 

 indicated dorsal to the shell gland; ova very few, one or two, 

 between testes and ventral sucker; vitellaria diffuse, from posterior 

 end to oral sucker ; posterior excretory vessel large. A characteristic 

 feature of these distomes is the large size and small number of 

 the ova. No more than two ova were seen l^n any one of them. 

 Some of the smallest were immature, and contained no ova, but ova 

 were present in quite small specimens. Thus, one, length, 0.28 mm., 

 breadth, 0.27 mm., contained one ovum 0.10 by 0.06 mm.; another, 

 length, 0.28 mm., breadth, 0.25' mm., contained two ova, 0.10 by 0.05 

 mm. and 0.10 by 0.06 mm. Measurements of one in balsam : Length, 

 0.42 mm. ; breadth, 0.36 mm. ; oral sucker, length, 0.09 mm., breadth, 

 0.10 mm.; pharynx, length, 0.05 mm., breadth, 0.05 mm.; ventral 

 sucker, length, 0.06 mm., breadth, 0.06 mm. ; ova, 0.10 by 0.06 mm. 



From white perch: Eight (U.S.N.M. No. 8279), collected August 

 8, 1910. Six fishes examined. Measurements, life, moderately com- 

 pressed: Length, 1.04 mm.; breadth, 0.05 mm.; oral sucker, length, 

 0.1 mm., breadth, 0.11 mm.; pharynx, length, 0.06 mm., breadth, 

 0.04 mm.; ventral sucker, length, 0.10 mm., breadth, 0.09 mm.; ova, 

 0.11 by 0.07 mm. ; ova 5 in number. Prepharynx and esophagus each 

 shorter than pharynx; genital pore to left of median line; a second 

 seminal vesicle noted ; testes oblique ; yoke reservoir between testes and 

 ovary; seminal receptacle near median line in front of testes; shell 

 gland in front of seminal receptacle; ovary in one appeared to be 

 slightly lobed; vitellaria extend about to level of pharynx. 



From winter flounder : Distomum areolatuTu Rudolphi, Bull. U. S. 

 Fish Comm. for 1899, 1901. 



From cunner: Distomum areoJafum Rudolphi, Bull. U. S. Fish 

 Comm. for 1899, 1901. A reexamination of these distomes shows 

 that they belong here. They are densely spinose, broadest about the 



