ART. 16. HELMINTH PARASITES OF THE OPOSSUM CHANDLER 



■'■■■ '±'-if:'i\':t^\\M 



lies anterior to the testes, sometimes to the right and sometimes to 

 the left of the median line. The shell gland is inconspicuous in 

 whole mounts; it lies in close proximity to the ovary. The upper 

 part of the uterus is enlarged to serve as a seminal receptacle ; from 

 the region of the anterior edge of the ovary the uterus proceeds, as 

 a very broad, thin-walled tube, in almost a straight line to the genital 

 atrium. The vitelline glands occupy a large part of the body, occur- 

 ring in a considerable part of the anterior portion of the body, for- 

 ward to the intestinal bifurcation, in the holdfast organ, and in the 

 areas between and around the sex glands; some follicles are found 

 even behind the posterior testis. There is a 

 large yolk reservoir situated on the median line 

 between the testes. The uterus contains only a 

 few eggs, from 1 to 7 or 8; these vary in meas- 

 urement from 86/x to 100/^ in length and from 

 60fx to G3ju, in width. 



Host. — Didelphls virglniana. 



Location. — Small intestine. 



Locality. — Houston, Tex. 



Type specimen. — U.S.N.M. Helm. Coll. No. 

 8544 ; paratypes. No. 8545. 



Remarhs. — This fluke is remarkable for the 

 extreme diversity of form that it can assume; 

 for a long time it was difficult to believe that 

 only one species was represented. The prob- 

 lem is further complicated by the fact that 

 LaRue and Bosma (1927) have described an- 

 other holostome from the opossum in Texas, 

 under the name Neodiplostonium lucidum. In 

 spite of the wide variation in form of the 

 species here described, there can be little doubt 

 that Neodiplostomnm lucidum is specifically 

 distinct. It is described as being unusually transparent after 

 preservation, which is not true of Proalana variahilis. None of 

 seven specimens of the former species showed evidence of lateral 

 sucking cups or tentacular appendages, whereas this condition is 

 exceptional in the present species. LaRue and Bosma's species also 

 differs in its much greater slenderness, in the acetabulum being 

 smaller than the oral sucker, in the shape of the holdfast organ, 

 in the shape of the testes, and in the simple coil of the seminal vesicle. 

 Ncodiplostomum lucidum has subsequently been found by Dikmans 

 (1931) in opossums in Louisiana. 



o.s*nm. 



Figure 2. — Large speci- 

 men of Proalaria vari- 

 abilis, new species 



