566 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 57. 



genital sinus, and two muscular bulbs, lenticular in shape, on the 

 right and left sides of the genital sinus. Prostatic portion of vas 

 deferens well developed, situated behind and to the left of the 

 ventral sucker. In the left side of the median field behind the pros- 

 tatic portion of the vas deferens a large U-shaped seminal vesicle, the 

 base of the U being slightly to the right of the median line. Testes 

 oval, transversely elongated, in posterior sixth of body, meas- 

 uring 75 to 135 [I by 50" to 95 [jl. Seminal receptacle may attain 

 a size of 100 by 75 [jl, situated about in the median line just in front 

 of the testes. Ovary globular or oval, 80 to 130 [jl in its major di- 

 ameter, in front of the right testis ventral of and to the right and 

 in front of the seminal receptacle. Distance of center of ovary 670 

 to 800 [I (four-fifths the body length or a little more) from the 

 anterior end of the body. Vitellaria in the posterior end of the 

 body, consisting of 2 to 6 lobules in each lateral field, anterior limits 

 in the posterior portion of the zone occupied by the ovary and 

 seminal receptacle. A transverse vitelline duct extends inwards 

 from the anterior portions of the vitellaria from each side, the two 

 uniting near the median line, the right and left duct, respectively, 

 passing on the ventral side of the ovary and seminal receptacle. 

 Uterus forms four or five transverse loops in the median field, 

 ventral of the seminal receptacle, ovary, and seminal vesicle, and 

 often extending into the lateral fields on the ventral side of the 

 intestinal ceca. Eggs, yellowish-brown, 16 to 18 pi long by 9 to 

 11 |x wide. 



Host. — Alaskan fox {Vulpes lagopus). 



Location. — Intestine. 



Locality collected. — Washington, District of Columbia (National 

 Zoological Park). 



Type specimens. — United States National Museum Helmintho- 

 logical Collections No. 4448, collected by Dr. H. W. Graybill, May 2, 

 1906. 



ASCOCOTYLE NANA, new species. 



Fig. 30. 



1920. Ascocotyle nana Ransom, 1920 (the present paper), (in Vulpes 

 lagopus; U. S.). 



Specific diagnosis. — Ascocotyle: Length, 0.61 to 0.79 mm.; max- 

 imum width, 0.275 to 0.38 mm.; outline of body piriform. Cutane- 

 ous scales about 4 pi. long by 2 \j. wide. Circumoral spines 16 to 20 in 

 number, 8 to 12 pi long, dorsally arranged in a double row, ventrally 

 in a single row. Dorsal lip short, rounded, not triangular in out- 

 line. Oral sucker 35 to 45 pi, wide, 40 to 50 \l long, with a small hol- 

 low oral cecum 30 to 60 pi long, 8 to 12 p. wide, terminating in a point 

 posteriorly. Pharynx globular or cylindrical, 32 to 40 [j, wide, 32 



