Crossocephalus from the Rhinoceros. 



97 



parus, according to the descriptions of v. Linstow (1899) and 

 of Gedoelst (1916), are : — 



(1) The much greater length of the tail in the female. 



(2) The absence of a second, flattened pair of neck- 



papillee behind the cuticular collar bearing the 

 long ear-like papillae. 



(3) The absence of the six curved anterior spines 



(" crochets" of Gedoelst; " Haken " of v. Linstow) 

 on the lips when the jaws are in the inverted 

 position. 



(4) The larger number of caudal papillae in the male. 



The following comparative table of measurements in the 

 two species may serve to complete the foregoing account. It 

 will be observed that the correspondence between them is 

 remarkably close, the most striking exception being the 

 length of the tail in the female. All the measurements are 

 in millimetres. The figures in square brackets have been 

 calculated from v. Linstow's fractional measurements : — 



As regards the structure of the mouth-parts, it has already 

 been stated that some confusion exists in the descriptions of 

 C. viviparus. This appears to have been due to the fact 

 that v. Linstow (1899) saw examples with the jaws in both 

 positions — everted and inverted, — whereas Gedoelst (1916) 

 was dealing only with specimens having the jaws inverted 



