TREMATODES FROM FISHES — LINTON 



29 



Record of collection.— T\no (U.S.N.M. No. 8173), collected Sep- 

 tember 20, 1912 ; length in formalin, 3 imn. ; breadth, 1 mm. 



PROSORHYNCHUS OVATUS (Linton) 



Plate 18, Figures 243, 244 



Monostomum orMctilare Rudolphi, Linton, Proc. U. S. Nat. Mus., vol. 20, pp. 



541, 542, pi. 54, figs. 2-5, 1899. 

 Oasterostomum ovatum Linton, Bull. U. S. Fish Comm. for 1899, p. 297, 1900; 



ihid., p. 457, 1901. 

 Prosorhynchus ovatus (Lintou), Doixfus, Fauna des Colonies Frangaises, 



Helmintha, vol. 1, pp. 100-105, figs. 14-17, 1929. 



Since earlier descriptions of this species have been lacking in some 

 particulars, the following emended description is given: 



Body ovate, depressed, flattened ventrally, convex dorsally, covered 

 with minute spines ; broadest as a rule about at the level of the ventral 

 sucker, which is not far from the anterior third ; broadly rounded at 

 the anterior end and usually tapering posteriorly to a bluntly rounded 

 point. Anterior sucker subterminal, nearly circular; ventral sucker 

 approximately one-half the diameter of the anterior sucker. The 

 sacculate intestine extends forward from the ventral sucker and gives 

 off a slender cecum from its dorsal side, which extends back about to, 

 or a little beyond, the posterior end of the second testis, its posterior 

 end lying between the second testis and the anterior half of the cirrus- 

 pouch. Testes two, on the right side, somewhat variable in shape, 

 in some cases being longer than broad, in others broader than long, 

 and in yet others circular in outline, close together, usually somewhat 

 diagonally placed. The cirrus pouch lies on the left side of the 

 median line, its anterior end, which encloses the seminal vesicle, 

 extending forward about to the level of the anterior edge of the 



Table 8. — Measurements of five specimens of Prosorhynchus ovatus in balsam. 

 {1 to 4, whole mounts; 5, frontal sections) 



Measurement 



Length 



Breadth, level of anterior sucker 

 Breadth, level of ventral sucker. 



Breadth, near posterior end 



Anterior end to ventral sucker... 



Anterior sucker, length 



Anterior sucker, breadth 



Diameter of ventral sucker 



Ovary, length 



Ovary, breadth 



First testis, length 



First testis, breadth 



Second testis, length 



Second testis, breadth 



Mm. 



3.15 

 .63 



1.22 

 .56 

 .98 

 .26 

 .26 

 .15 

 .24 

 .21 

 .49 

 .31 

 .60 

 .28 



Mm. 



2.84 

 .70 



1.28 

 .56 



1.07 

 .25 

 .24 

 .15 

 .30 

 .22 

 .52 

 .42 

 .62 

 .35 



Mm. 



2.52 

 .63 



1.26 

 .49 

 .95 

 .28 

 .32 

 .16 

 .30 

 .22 

 .36 

 .32 

 .35 

 .36 



Mm. 



2.24 

 .70 



L26 

 .49 

 .71 

 .25 

 .28 

 .16 

 .21 

 .16 

 .28 

 .29 

 .32 

 .32 



Mm. 

 1.68 

 .36 

 .63 

 .28 

 .63 

 .16 

 .20 

 .12 

 .18 

 .14 

 .22 

 .18 

 .24 

 .17 



