1932 ANNUAL REPORT. 1931 29 



Psilostomum ondatrae. Price, 1931. 



Collected from the liver of a muskrat in the vicinity of the Experimental 

 F'ur Farm and forwarded to Dr. Emmett W. Price, Zoological Division, Bureau 

 of Animal Industry, Washington, D.C., who described it as a new species. Pro- 

 ceedings U.S. National Museum, Vol. 79, Art. 4, as follows: 



Body ovoid, 1.6 mm. to 2 mm. long by 0.315 mm. to 0.961 mm. wide in 

 the region of the anterior testis, flattened dorsoventrally. Cuticular spines 

 were not found on specimens from the muskrat. Oral sucker subterminal, 

 0.150 mm. to 0.155 mm. in diameter; oral aperture slitlike to oval in shape. 

 Acetabulum transversely elongated to almost circular in shape, strongly mus- 

 cular, 0.220 mm. to 0.300 mm. by 0.300 mm. to 0.375 mm., situated 0.525 mm. 

 to 0.537 mm. from the anterior end of the body. Prepharynx 0.38 mm. to 

 0.75 mm. long, the length depending on the amount of contraction of the anterior 

 part of the body. Pharynx strongly muscular, 0.112 mm. to 0.127 mm. long 

 by 0.82 mm. to 0.105 mm. wide. Oesophagus slender, 0.75 mm. to 0.112 mm. 

 long; intestinal ceca simple, extending to within a short distance of the posterior 

 end of the body. Excretory pore terminal. Testis large, elongated transversely, 

 postequatorial and tandem in position. The anterior testis is 0.262 mm. to 

 0.375 mm. long by 0.412 mm. to 0.712 mm. wide and the posterior testis 0.262 mm. 

 to 0.275 mm. long by 0.337 mm. to 0.750 mm. wide. Cirrus pouch piriform, 

 its posterior end never extending beyond the centre of the acetabulum; it con- 

 tains a voluminous seminal vesicle and a long, slender, unarmed cirrus. The 

 genital pore is situated in the median line about midway betwesn the bifurcation 

 of the intestine and anterior margin of the acetabulum. Ov^ary ovoid, 0.75 mm. 

 by 0.150 mm., situated a short distance in front of the anterior testis and to 

 the median line. Shell gland well developed, dorsal of ovary. Laurer's canal 

 present. Receptaculum seminis apparently absent. The vitellaria are com- 

 posed of large follicles situated laterally and forming a wreathlike mass extending 

 from the level of the pharynx to the posterior end of the body. Uterus relatively 

 short, consisting of irregular coils occupying the intercecal space between the 

 anterior margin of the anterior testis and the acetabulum, and terminating in a 

 moderately de\'eloped metraterm. The metraterm extends along the left side 

 of the cirrus pouch and opens into the genital sinus immediately anterior to 

 the male aperture. 



Eggs oval, 0.82 mm. to 0.90 mm. long by 0.45 mm. to 0.48 mm. wide, yellowish 

 i)rown in colour. 



Echinostomum coalitum. Barker and Beaver, 1915. 



Found in the duodenum of muskrats in the vicinity of Kirkfield, Ontario. 

 This is one of the longest trematodes infesting muskrats. The body is long and 

 narrow, length 16 mm. to 23 mm. Width anterior to testis 1.21 mm. to 1.98 mm. 

 Head collar, kidney shaped, well developed, equijjped with double row of spines. 

 Prepharynx connects with oral sucker, which is 0.291 mm. to 0.35 mm. in diameter. 

 Oesophagus comparatively long, 1.14 mm. in length. Ventral sucker large and 

 muscular, 1.14 mm. to 1.30 mm. long by 0.97 mm. to 1.01 mm. wide. Cirrus 

 sac prominent, terminating above ventral sucker, containing well developed 

 cirrus. Ovary broader than long and well marked, width 0.485 mm. to 0.399 mm., 

 length 0.399 mm., situated in median line, directly anterior to testis. Testis 

 tandem, more or less elliptical with indented margins, situated in posterior end 

 of body; length 1.28 mm. to 0.873 mm., width 0.485 mm. to 0.582 mm. \'itel- 

 laria extend from short distance posterior to ventral sucker, gradually becoming 



