NEMATODE GENUS PHYSALOPTERA. 



1029 



walled vagina, about 1*1 mm. long and 100 /i in diameter. The 

 following egg-chamber is about 3/4ths of the length of the vagina 

 and about twice as broad. The common trunk is very short, so 

 that in some cases it appears to be absent ; its posterior end 

 divides into two branches, each of which connects up with one of 

 the two utei-i. 



The i-eceptacula seminis are slighth' oval, 380 /i long by 280 u 

 broad ; they are distinctly constricted off from the oviducts, but 

 their junction with the uteri is very gradual. 



The eggs, which on the average are 43 f.i long and 27 // in 

 diameter, contain fully-developed embryos in iitero ; they are 

 thick-shelled and oval. 



Male. 



The males are much smaller than the females, the longest 

 measuring 20 mm. long and 570 /.« broad. Anteriorly the body 



Text-fi2-ure 12. 



Fhysaloptera retusa Rud. 

 A = Left spicule. B = Right spicule. 



C = Caudal extremity of male. 

 (The scale alongside B refers also to A.) 



tapers vei"y gradually, but posteriorly hardly any narrowing 

 takes place until a very short distance in front of the bursa ; 

 here the thickness becomes sharply less, so that at the juncture 

 of the bursa it is only about 3/4ths of the thickness further 

 forwards. 



The male bursa is large, measuring about 2-3 mm, long by 

 1-1 mm. broad in the largest specimens, and is sharply reflected 

 ventralwards. The cuticular expansions are well developed, and 

 the four pairs of pedunculated papillae supporting them are 

 situated equidistant from each other, two pairs being pre-anal 

 and two pairs post-anal. The ventral surface of the bursa is 

 covered by numerous longitudinal rows of small pi-otuberances. 



Proc. Zool. Soc— 1922, No. LXIX. 69 



