2 PROCEEDINGS OF THE NATIONAL MUSEUM VOL.79 



Female: 6.5 mm. long, tightly rolled in about 10 to 12 spirals. 

 The muscular ovejector is about 160/t to 180/a long. The tail ends 

 in a blunt point. The distance from the vulva to the anus is 120/x, 

 and from the anus to the tip of the tail 40ju,. The lips of the vulva 

 are slightly elevated above the body margin. Eggs, 55ju, by 40/i. 



The single ovary, uterus, and ovejector in the female place this 

 nematode in the family Heligmosomidae. It has been placed in the 

 genus Viannaia because it resembles the members of this genus in 

 the formula of the rays of the bursa and in the absence of marked 

 longitudinal cuticular striae. It differs from them in the much 

 greater length of the spicules, the greatest length of the spicules for 

 the species previously included in the genus being 255ja. It resem- 

 bles the genus Longistriata in the length of the spicules but differs 

 from it in the absence of the longitudinal cuticular striations char- 

 acteristic of the genus. It differs from both genera in the presence, 

 within the bursa, of a dense cuticular swelling, which renders the 

 study of the origin of the rays very difficult. Two sets of specimens 

 were available for study. The nematodes in the first set were collect- 

 ed alive and were killed and fixed in hot alcohol and glycerine. The 

 second set was collected from the viscera of an opossum sent to the 

 laboratory from Louisiana, and this material was preserved in forma- 

 lin. In the first set, killed and fixed in hot alcohol, the structure 

 within the bursa is quite noticeable. In the second set of specimens 

 this structure seems to have partly disintegrated, and the bursal 

 rays can be studied with less difficulty. 



Host. — Opossum {Didelphys virginiana). 



Location. — Small intestine. 



Locality. — Jeanerette, La. 



Type specimen.— U.S. '^M. Helm. Coll. No. 31391. 



A NOTE ON GNATHOSTOMA TURGIDUM AND OTHER PARASITES OF 



THE OPOSSUM 



Among the nematodes collected from the stomach of the opossum 

 there was found one male gnathostome. This specimen resembles in 

 a general way Gnathostoma turgidum Stossich, 1902, as redescribed 

 by Travassos (1925), but differs from it in one respect. It agrees 

 with Gnathostoma turgidum, in its host, both being collected from 

 the opossum, in its size, in the number of rows of spines on the head 

 bulb, in the character and extent of the body spines, and in the size 

 of the small spicule. The spines on the body immediately behind 

 the head are broad and short with 10 to 12 teeth, the spines immedi- 

 ately behind the esophagus are leaf -like with about 6 teeth, the spines 

 near the end of the spinous area have 3 teeth, then follow spines 

 with 2 teeth, succeeded in turn by single-toothed spines in densely 



