ABT.i TREMATODE PARASITES OF BIRDS LINTON 5 



ova, collapsed and difficult to determine the exact diameters, longer 

 diameter from 0.06 to 0.08, shorter diameter from 0.03 to 0.04. 

 Type.— Cat. No. 7917, U.S.N.M. 



PSILOSTOMUM PLICITUM, new species 

 Figure 7 



The following description is based on a single specimen mounted 

 in balsam. It is from the intestine of a herring gull {Larus argen- 

 tatus) and was collected at Woods Hole, but the date of collecting is 

 missing. 



Body elliptical in outline, longer than broad; margins of neck 

 folded ventrally and projecting in front of the ventrally placed oral 

 sucker; ventral sucker at about the anterior third and of about the 

 same size as the oral sucker; pharynx relatively large, adjacent to 

 oral sucker ; esophagus none ; rami of intestine begin at anterior edge 

 of ventral sucker and extend to the posterior end; genital pore in 

 front of ventral sucker, about at the level of the posterior end of the 

 pharynx ; cirrus-pouch at left side of ventral sucker, somewhat elon- 

 gate, its posterior end functioning as a seminal vesicle ; testes two, at 

 about the posterior third, contiguous. The posterior testis is about 

 on the median line, the anterior, for the most part, to the right of 

 the median line. The ovary is at the antero-median border of the 

 first testis. It is made up of small, rounded lobes, which give to it a 

 morulalike effect. Near its postero-median border there is a seminal 

 receptacle. The vitellaria fill the greater part of the body from 

 the posterior end as far forward as the level of the middle of the 

 ventral sucker. The uterus is between the ventral sucker and the 

 ovary. The metraterm, dorsal to the ventral sucker, appears to have 

 rather thick, muscular walls ; ova few. 



Dimensions in balsam : Length 1.68 mm ; maximum breadth, about 

 the middle, 0.84; diameter of oral sucker 0.20, of pharynx 0.13, of 

 ventral sucker 0.18; ova 0.06 by 0.04. 



Type.~Cat. No. 7918, U.S.N.M. 



PSILOSTOMUM VARIUM. new apecies 

 Figure 9 



A single distome, found in the inetstine of a loon {Gavia immer), 

 at Woods Hole, September 1, 1911, is here described. 



The following color notes were made on the living worm : General 

 color effect purple. When the specimen was compressed the testes 

 and ovary were seen to be a very brilliant magenta ; the cirrus-pouch 

 faint pink; rami of intestine throughout faint reddish; the very 

 voluminous vitellaria dull, opaque magenta. 



