TREMATODES EROM FISHES — ^LINTON 39 



Family STERINGOPHORIDAE Odhner, 1911 



Subfamily Steringophorinae Odhner, 1911 



Genus STERINGOPHORUS Odhner, 1905 



STERINGOPHORUS FURCIGER (Olsson) 

 Plate 19, FiGtmES 260-265 ; Plate 20, Figures 266, 267 



Leioderma furcigenim Olsson, Stafford, Zool. Auz., vol. 27, p. 486, 1904. 

 Steringophorus furciger (Olsson), Odhner, Die Trematoden des arktischen 



Gebietes, pp. 305-310, pi. 2, figs. 6, 7, 1905. 

 Steringophorus furciger (Olsson), Nicoll, Parasitology, vol. 6, pp. 190, 192, 



1913. 

 Steringophorus furciger (Olsson), Fuhemann, Kiikenthal-Krumbacli's Hand- 



buch der Zoologie, vol. 2, p. 38, fig. 39, 1928. 



Distomes collected by Vinal N. Edwards from the four-spotted 

 flounder and the winter flounder are here recorded. 



Note made after preliminary examination of formalin material: 

 Outline oval, tapering to blunt extremities, varying from short oval 

 with breadth nearly half the length, to linear oval with breadth but 

 little more than one third the length ; translucent, with cirrus pouch 

 and vitellaria showing as white opaque spots; uterus with smoky- 

 brown ova; aperture of ventral sucker in most cases transverse. 



The following description is based on whole mounts in balsam and 

 on series of sections : 



Body long-ovate, smooth, tapering to each end; posterior end a 

 little more pointed than anterior. Oral sucker circular, ventrally 

 placed; no prepharynx; pharynx much smaller than oral sucker; 

 esophagus as long as or longer than pharynx; intestinal rami begin 

 about halfway between oral and ventral suckers and extend to a point 

 not far from halfway between the ventral sucker and the posterior 

 end ; ventral sucker broader than long, much larger than oral sucker. 

 Cirrus pouch large, between intestinal rami and ventral sucker, its 

 thick walls abundantly supplied with prostatic cells. Ovary morula- 

 like, mainly on right side of median line between the right testis 

 and the ventral sucker; vitelline glands two, lateral to testes and 

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

 ventral sucker. The uterus proceeds from the shell gland, just behind 

 the ovary, forward to the ventral sucker, then turns and passes back 

 between the testes and fills the greater part of the posttesticular 

 space; returning, the uterus, or metraterm, passes on the dorsal side 

 of the ventral sucker, on the left side of the cirrus pouch to the geni- 

 tal pore. The excretory vessel is a single dorsal tube from the poste- 

 rior end to a point between the testes, where it divides into a right 

 and a left branch, which extends to the anterior end. Laurer's canal 



