No. 2322. TREMATODE FAMILY HET EROPHY ID AE— RANSOM. 587 



to 45 [A long, located 125 to 185 (x from the anterior end of the body, 

 40 to 100 [J, in front of the bifurcation of the intestine. Intestinal 

 ceca extend some distance posterior of the level of ventral sucker, 

 posterior ends hidden by the coils of the uterus. Ventral sucker 

 365 to 465 [X from the anterior end of the body, 45 to 70 [jl in 

 diameter. In relation with the genital sinus on the left of the 

 median line in front of the ventral sucker a lenticular muscular 

 body, 40 to 45 ^ wide and about 16 [x long. Testes globular or oval, 

 70 to 120 [X wide by 55 to 100 [x long. Seminal receptacle median, 

 dorsal, just in front of testes. Ovary globular or oval, ventral, just 

 in front of right testis, 55 to 80 [x wide, 50 to 100 \i long. Vitellaria 

 ventral and lateral in position, in the zone occupied by the ovary 

 and testes, not extending forward beyond the level of the anterior 

 border of the ovary, and consisting of five or six relatively large 

 lobules on each side of the body. Transverse vitelline ducts in the 

 neighborhood of the boundary between the ovarian and testicular 

 zones. Uterus a mass of coils filling up most of the body between the 

 testes and ventral sucker, concealing the posterior ends of the in- 

 testinal ceca. Eggs 18 to 24 pi long, 10 to 16 [x wide. 



Host. — Alaskan fox (Vulpes lagopus). 



Location. — Intestine. 



Locality collected. — Washington, District of Columbia (National 

 Zoological Park). 



Type specimens. — United States National Museum Helminthologi- 

 cal Collections No. 19030, collected by H. W. Graybill, May 2, 1906. 



A. nana is very similar in appearance and in many of its struc- 

 tural details to Pygidiopsis genata Looss, 1907, found in Pelecanus 

 onocrotalus., at Cairo, Egypt. P. genata, however, is somewhat 

 smaller (0.3 to 0.4, or if expanded, nearly 0.5 mm. in length), and 

 no circumoral crown of spines or oral cecum is present. Apparently, 

 also, P. genata is much more deeply concave on its ventral surface 

 than A. nana. Otherwise the characters of P. genata including the 

 presence of a lenticular organ on the left side of the genital sinus, 

 distribution of the vitellaria, size of the eggs, etc., correspond almost 

 exactly to those of A. nana. As Looss (1907, p. 490) remarks, 

 Pygidiopsis is evidently very closely related to Ascocotyle. The 

 great similarity of P. genata (the only and type species of Pygidiop- 

 sis) to Ascocotyle nana lends additional weight to Loess's remark as 

 to the relationship of Pygidiopsis. 



The type specimens of A. nana were taken from the intestine of 

 the same fox that harbored the type specimens of A. long a. 



It is possible that A. nana may be the same as the form very im- 

 perfectly described as A. italica by Alessandrini (1906), who col- 

 lected it from a dog in Italy. A. italica, like A. nana, has a very 

 small oral cecum, and apparently has a similar dorsal lip, similar 



