310 



PARASITIC WORMS. 



of each lip bears three papillae ; a small median, lateral papilla 

 which scarcely breaks the surface of the cuticle,* and 



Fig. 4. Physaloptera mydai. Head of female; dorsal view. I, lateraj 

 pajjilla; s, subdorsal papilla. 



prominent, dome-shaped subdorsal and sub ventral papillae 



The usual teeth are 



present on a median 



prominence at the 



extremity of the lip 



— a blunt external 



tooth and a trip- 



a r t i t e internal 



tooth, the median 



cusp of which is 



slightly smaller 



than the others. At 



the base of the 



median prominence 



there are two pairs of small refringent points, possibly denticles. 



Towards the dorsal and ventral sides of the dentigerous surface 



there are also two large, prominent, rounded processes, which 



can hardly be described as teeth. On the ridges connecting 



these with the median prominence there may be several small 



H 



Fii 



O'l mm 



5. Physaloptera mydai. Lip of female, 

 viewed from imier surface. 



* Ortlepp (1922) doubts the presence of a lateral papilla in Physaloptera. 



'It is a very remarkable fact if this papilla is really absent in most species 



of Physaloptera, since in all other Nematodes with two lateral lips, in 



which it has been carefully looked for, such a papilla has invariably 



been found. 



