NEMATODE GENUS PHYSALOPTERA. 



1033 



about l/9tli and in the male about l/7th of the total body- 

 lengtli. Its muscular part is slightly thinner, and the nerve 

 ring is situated in its last quarter. 



Female. 



Tlie females are rather slender, mature worms varying from 

 28 to 47 mm. long by 650 to 720 fi thick in their posterior third. 

 The body is much attenuated in its anterior half and in its posterior 

 quarter. The tail is short and bluntly conical, and forms l/80th 

 of the body-length ; its caudal pores are situated behind its 

 middle, and their position divide the tail in the ratio of 3 : 2. 



The vulva is situated on a slight elevation at the junction of 

 the 1st and 2nd quarters of the body. It leads into a straight 

 vagina 1*5 mm. long by 65 /x thick; the following egg-chamber 

 is oblong and 640^ long by 175/^ broad; the common trunk is 



Text-fisfure 15. 



Fhi/saloptera ohtusissima Mol. 

 Caudal extremity o£ male. 



short, and half again as thick as the vagina ; it is 320 /x long, and 

 its posterior end divides to give rise to two branches, each of 

 which joins up with a uterus. The proximal parts of the uteri 

 may be much convoluted in some individuals ; posteriorly each 

 terminates in a receptaculum seminis, which is long and oval, 

 measuring 400 ji long by 160 /.i broad. 



The eggs are fully embryonated in uiero ; they are oval and 

 thick-shelled, and measure 45 by 26 /.i. 



Male. 



The males are comparatively stouter than the females ; they 

 vary in length from 20 to 32 mm., with a maximum thickness of 

 700 to 720 jn. The body is attenuated only in its anterior third. 



The caudal bursa is elongate and somewhat lanceolate in 

 shape; its alae are well developed and its ventral papillae are 



