NEMATODE GENUS PHYSALOPTERA. 1077 



respectively 55 and 90 mm. long, with a maximum breadth of 1"9 

 and 2'9 mm. respectively ; the body is attenuated only in its 

 anterior half, the posterior half being of the same thickness, 

 •except for the tail region, where the body tapers abruptly to form 

 a conical tail l/85th of the total length. 



The vulva opens very far forwards, being situated in front of 

 the middle of the oesophagus ; its position in one specimen 

 divided the body in the ratio of 1 : 22. It leads into a com- 

 paratively straight vagina 2| mm. long by 115 /x broad. The 

 following egg-chamber is club-shaped, 2 mm. long by about 840 /x 

 broad at its widest part ; many uteri take their origin from the 

 outer edge of the club ; 15 were present in the one specimen, and 

 in the other at least 12 could be made out. 



The eggs are oval and thick-shelled, averaging 39 yu, long and 

 27 /A broad. 



Male. 



The males are smaller than the females, measuring respec- 

 tively 47 and 55 mm. long by 1*45 and 1*6 mm. broad. The 

 body has its maximum breadth just in front of the bursa, and 

 from here the body attenuates gradually towards the anterior 

 end. 



The bursa is broad and sharply recurved ventralwards ; it forms 

 about 1/1 6th of the body-length, and its ventral surface is 

 covered with longitudinal rows of tubercles. The four pairs of 

 pedunculated papillce are equidistant, three paii's being pre -anal 

 and the 2nd and 3rd pairs are much longer than the other pairs ; 

 of the pre-anal ventral papillas, the middle one is slightly larger 

 and' is situated nearer the anus. There are five pairs of post-anal 

 ventral papillae, of which the 1st and 2nd pairs are small and 

 situated in a row immediately behind the anus ; the 2nd, 3rd, 

 and 4th pairs are equidistant from each other, while the distance 

 between the 4th and last pair is only about a third the distance 

 separating the two preceding pairs. 



The spicules appear to be short and equal, but unfortunately 

 the tip of the right spicule was broken off in both specimens, so 

 that it was not possible to determine its correct length ; the left 

 spicule was straight and pointed, and measured 655 jx long by 

 57 /A broad at its base : the base of the right spicule had the same 

 thickness as that of the left side. 



Host : Lagothrix humholdtii. Stomach. Brazil. 



Affinities. — This species appears to be closely i-elated to 

 Ph. turgida, v/ith which species it agrees in the form of the lips 

 and teeth, general size, and in the anatomy of the female 

 genitalia. It is, however, readily distinguished from this species 

 by the position of the vulva, the difference in the relative length 

 of the cesophagus in the two sexes, and by the position of the 4th 

 and 5th post- anal ventral papilise on the male bursa. 



Pjioc. Zool. See— 1922, No. LXXII. 72 



