A NEW NEMATODE WORM, VIANNAIA BURSOBSCURA, 

 FROM THE OPOSSUM, WITH A NOTE ON OTHER PARA- 

 SITES OF THE OPOSSUM 



By G. DiKMANS 



Associate Parasitologist, Zoological Division, Bureau of Animal Industry^ 

 United States Department of Agriculture 



The nematode described in this paper was found in some parasitic 

 material collected from a number of opossums at the laboratory of 

 the zoological division at Jeanerette, La. 



VIANNAIA BUKSOBSCURA, new species 



Plate 1; Plate 2, Figuee 1 



SpedfiG diagnosis. — Viannma: Small, spirally coiled nematodes, 

 bright red when freshly collected. Cephalic cuticle inflated, marked 

 with distinct annular striations; cuticular inflation 90^ to 100/x long 

 and 38ju, to 40|a wide. Cuticle elsewhere marked with extremely fine 

 transverse and longitudinal striations. Thickness of head 27ju, with- 

 out the cuticular inflation. Esophagus 350jii to 400/i long and 35/a 

 wide at its termination. 



Male: 4.5 mm. long and 75/x wide at its widest portion just anterior 

 to the bursa. The bursa consists of two lateral, symmetrical 

 lobes. The ventral and lateral rays arise from a common trunk. 

 The ventral rays are separate and directed forward, reaching the 

 margin of the bursa, the latero-ventrals pushing the margin of the 

 bursa slightl}'- beyond the general contour. The lateral rays are 

 comparatively short; the externo-laterals are directed slightly for- 

 ward, diverging from the other laterals; the medio-laterals and 

 postero-laterals are parallel; the medio-laterals are the thickest of 

 the rays and they curve distally before reaching the bursal margin ; 

 the postero-laterals are straight. The externo-dorsal rays are very 

 delicate and slender with slightly curved tips ; the dorsal ray has two 

 long bifurcations, which apparently again divide at the tips; the 

 dorsal and externo-dorsal rays are extremely difficult to find and to 

 study because they are obscured by a dense cuticular extension on the 

 inside of the bursa. The spicules are filiform and are 630^ to 650/* 

 long. Gubernaculum present, lightly chitinized, about 55/t to 60/* 

 long. 



No. 2897.— Proceedings U. S. National Museum Vol. 79, Art. 31. 

 66995—31 l 



