568 PROCEEDINGS OP THE NATIONAL MUSEUM. vol.57, 



intestinal ceca, a similar distribution of the vitellaria and a similar 

 uterus, but inasmuch as Alessandrini states that A. itcdica is similar 

 to Looss's species, A. minuta, except for certain differences that he 

 names, it must be presumed that A. nana is distinct from A. italica 

 in view of the fact that it presents differences from A. minuta not 

 mentioned by Alessandrini. 



Genus PYGIDIOPSIS Looss, 1907. 



Generic diagnosis. — Heterophyidae: Lateral borders greatly 

 curved ventralwards. Prepharynx long, about equal in length to 

 the esophagus. Bifurcation of the intestine nearer to the ventral 

 sucker than to the oral sucker. Intestinal ceca extend into the pos- 

 terior portion of body a considerable distance beyond the level of 

 the ventral sucker, but not as far as the testes. Genital sinus median, 

 immediately in front of the ventral sucker. A lenticular-shaped 

 body about half as large as the ventral sucker in relation with the 

 terminal portion of the vas deferens and the left half of the genital 

 sinus and protrusible through the genital pore. Prostatic portion 

 of vas deferens weakly developed. Seminal vesicle S-shaped. 

 Testes oval, side by side, near posterior end of body. Ovary globular, 

 in front of right testis near the ventral surface of the body. Seminal 

 receptacle large, globular, median, anterior of testes, near the dorsal 

 surface of the body. Vitellaria in lateral fields, ventral in location, 

 near posterior end of body, consisting of a few relatively large 

 lobules, limited to the region between the levels of the anterior 

 border of the ovary and the posterior borders of the testes. Trans- 

 verse vitelline ducts meet in median line ventral of seminal recep- 

 tacle. Uterus occupies most of posterior portion of body behind 

 the genital pore as far back as the testes. Vagina opens into the 

 right half of the genital sinus. Eggs about 20 [x long. 



Type species. — Pygidiopsis genata Looss, 1907. 



PYGIDIOPSIS GENATA Looss. 1907. 



Figs. 32, 33. 



1907. Pygidiopsis genata Looss. 1007, pp. 488-490, fig. 7 (type of Pi/gidiop- 

 sis; in Pelecanus onocrotahis; Egypt). 



Specific diagnosis. — Pygidiopsis : Length may be nearly 0.5 mm., 

 usually 0.3 to 0.4 mm.; maximum width, 0.2 to 0.22 mm. Lateral 

 edges of body much curved ventralwards. Oral sucker about 40 \t. 

 in diameter. Prepharynx long. Pharynx, 36 ^ long by 24 [i. wide, 

 about midway between the oral sucker and the bifurcation of the 

 intestine. Intestinal ceca terminate about midway between the level 

 of the ventral sucker and the level of the testes, turning toward the 

 median line and dorsalwards near their termination. Ventral sucker 

 37 to 39 \i. in diameter. Genital sinus immediately in front of the 



