NEMATODE GE^^US PHYSALOPTERA. 



1075 



The eggs are oval and tliick-shellecl and relatively narrow, 

 measuring 48 /x by 29"5 /a. 



Alale. 



The males are smaller than the females, apparently mature 

 specimens measuring from 21 to 32 mm. long by '950 to 1*25 mm. 

 thick ; the body is much more attenuated anteriorly than in the 

 females, this thinning beginning from aboxit the posterior third. 



The bursa is large, and has well-developed lateral expansions ; 

 the four pairs of pedunculated papillae are equidistant from each 

 other, two pairs being pre- and two pairs being post-anal in 

 position. Of the three pre-anal ventral papillae, the middle one 

 is situated nearer the anus than the other two. Behind the anas 

 there are five pairs of ventral papillas ; of these the 1st and 



'Text-figure 40. 



Pliysaloptera turgida Rud. 

 A = Lateral view of cephalic extremity. 

 B = Caudal extremitj' of male. 



2nd pairs are situated immediately behind the anus in a 

 row, the 3rd pair is slightly oblique in position, and the 4th 

 and 5th are situated close together. The ratio of the distances 

 separating pairs 2 and 3, 3 and 4 to 5, and 5 to the tip of the tail 

 is as 1 : 2 : 1 . 



The spicules are of equal length, short, straight, and tubular ; 

 each is about 410 /a long by 32 //, broad at its base. 



The ventral surface of the bursa is covered with longitudinal 

 protuberances. 



Hosts : Didelphys cancrivora. 



" Manicon." 



Didelphys virginiana. 

 Affinities. — See Ph. dilatdta. 



Stomach. 



Brazil . 

 West Indies. 

 Michigan, 



