118 ON HELODERMA HORRIDXJM AND H, STJSPECTUM. [Jan. 20, 



The probable affinities and phylogeny of these five groups are 

 expressed by the following diagram : — 



Rhiptoglossa. 



Pythonomorpha. Lacertilia 



Dolichosauria. 

 Fig. 6. 



Ophidia. 



f) 







^ \\ 



I ill 



Til yj Li' (^ 

 1/ I 



A. 



C. 



A. Hind limb of Dolichosaurus lesinends (after Kornhuber) ; B. of Edesto- 

 saurus (after Marsh) ; C. of Varamts ; D. of Chamceleon. 



These figures illustrate the principal modifications of structure of 

 the limbs in the four Suborders in which they are developed. 



