PROCEEDINGS OF THE NATIONAL MU.SEUM 



VOL. 76 



in size, ISG/x long by 125/x wide. Cirrus pouch absent. Seminal vesicle 

 slender and sinuous, its posterior end lying on a level with the center 

 of the acetabulum. Ovary trilobed, small, and situated about twice 

 its own length in front of the bifurcation of the excretory vesicle. 

 Keceptaculum seminis large and pyriform, and situated to the right 

 and caudad of the ovary. Vitellaria lateral, extending from a short 

 distance caudad of the esophagus bifurcation to the level of the 

 ovary. Uterus composed of close transverse coils which are filled 

 with small eggs. The genital pore is situated 400/x to GOOyu, from the 

 anterior end of body. Excretory system similar to that in other 

 species of the genus. Eggs oval, 22/a long by 11/a wide, and yellow- 

 ish brown in color. 



Host. — Mink {Mustela vlson). 



Location. — Gall bladder. 



Distrihution. — Canada (Kirkfield, Ontario). 



Type specimens. — United States National Museum Helminthologi- 

 cal Collection No. 28180 ; paratypes No. 28366. 



This species is much smaller than any of the other species of the 

 genus. It resembles P. interinedius in many respects but is more 

 transparent, the testes are oval instead of being lobed, and the egg 

 is slightly smaller. Since the specimens of both of these species are 

 fully mature, the writer feels that in view of a lack of information 

 in regard to the influence of different hosts on the size of trematodes 

 of this genus, these forms should be considered as separate species. 



For further comparison of the more important characters of the 

 species of Parametorckis, the following table is appended. 



Comparative table of characters of species of ParamctorcMs 



Body form.. 

 Size: 



Length,. 



Widths 

 Oral sucker _ 



Acetabulum. 

 Pharynx 



Ovary 



Intestinal ceca. 

 Testes 



Uterus 



Vitellaria. 



Receptaculum 

 seminis. 



Egg 



Parametorchis 

 complexus 



Linguiform. 



5 to 7 mm... 

 1.5 to 2 mm. 

 330 to 390m-- 



330 to 390m-. 



Trilobed. 

 Sinuous.. 

 Lobed... 



Rosette-shaped 



United in front of 



uterus. 

 Pyriform 



24Ai by 12m. 



Parametorchis 

 noveboracensis 



Linguiform. 



G to 6.3 mm.. 

 2.2 to 2.6 ram. 

 232 to 242m.-- 



232 to 242m by 281 to 



300m. 

 Trilobed 



Almost straight 



Almost round 



Rosette-shaped.. 



Not united 



Pyriform 



2S-32M by 15-1Sm- 



Parametorchis 

 intermedins 



Linguiform 



3 to 3.0 mm 



1 ram f 



155 to 262m by 232 to 



27Sm- 



150m by 200m 



170 to 180m by 140m- 



Trilobed 



Sinuous 



Lobed 



Compact transverse 



coils. 

 Not united 



Slightly twisted 



30m by 15m 



Parametorchis 

 canadensis 



Linguiform. 



1.7 to 2 mm. 



,590 to 687m. 



93 to 108m by 140 

 15.5m. 



125m by 140m. 



1C8 to 140m by 62 to 

 9)m. 



Trilobed. 



Slightly sinuous. 



Oval or slightly 

 lobed. 



Compact trans- 

 verse coils. 



Not united. 



Pyriform. 

 22m by Hm. 



