NEMATODE GENUS PHYSALOPTERA. 1037 



(12) Physaloptera phrynosoma, sp. n. (Text-figure 18.) 



Numerous specimens were collected from several lizards which 

 had died in the Gardens of the London Zoological Society ; 

 unfortunately only a few of the females are mature. 



The parasites are slender and much attenuated anteriorly; 

 their greatest diameter is in their posterior third. 



The cuticle is smooth (?), and is not reflected over the lips. 

 The cervical papillte are situated just in front of the level of 

 the junction of the two oesophageal parts, and tlie excretory pore 

 from 50 to 100 /.i behind them on the ventral sui-face. 



The two lips are somewhat conical, and each is surmounted by 

 a large conical tooth, which is inclined slightly outwards ; no 

 other, teeth are present. Each lip has two paj)ill3e on its outer 

 surface. 



The oesophagus is straight, and varies in the females from l/6th 

 to l/7th, and in the male it is slightly less than l/5th of the 

 total body-length ; its anterior muscular part passes gradually 

 into the following glandular part, there being little difference in 

 the diameters of the two. The nerve ring encircles its anterior 

 part just in front of the junction of its third and last quarters. 



Female. 



Fully mature females vary in length from 18 to 23 mm., with 

 breadth from 610 to 760 /jl in their posterior third. The genital 

 aperture is non_protuberant, and is situated more or less at the 

 junction of the first and second body thirds ; its position varies 

 slightly in difi"erent individuals, being sometimes slightly in front of 

 or slightly behind this level. It leads into a short and thick-walled 

 vagina, 380 /x, long by 38 /i in diameter ; this in turn leads into a 

 well-developed egg-chamber measuring 950 /.i long by 152 fx 

 broad ; the posterior end of this chamber narrows suddenly and 

 passes into a short common trunk, which after a very short 

 traject divides into the two uteri ; the uteri pass parallel to each 

 other into the posterior sixth of the body. 



The eggs are oval and thick-shelled ; they measure 50 /j. long 

 by 36 /i in diameter. 



The receptacula seminis are small and oval, measuring 133 u 

 by 86 jLt. 



The tail is relatively long and slender, forming l/36th of the 

 total length ; its caudal pores are situated just behind its middle. 

 Male. 



The males are much slenderer than the females, their average 

 length being 11 mm. by 470 fjL broad. The caudal bursa has well- 

 developed alse, and its ventral surface is covered with longitudinal 

 rows of small tubercles. Two pairs of the stalked papillee are 

 pre-anal, and two pairs are post-anal in position ; they are more 

 or less equidistant from each other, but the pre-anal pair nearest 

 the anus is slightly more dorsal in origin than the others. There 

 are three ventral pre-anal papillae, the median unpaired one being 

 situated nearer the anus than the other two. Immediately 



