AFFINITIES OF RANA SUBSIGILLATA. 



27 



species and comparing them with, for instance, those of R. brevi- 

 ceps and R. delalandii, it is indeed difficult to undei'stand how the 

 older authoi's (Tschudi, Dum6ril & Bibron, Gilnther, Peters, etc.) 

 can have placed them together in one genus {Pyxicephalus or 

 Tomopterna) merely on account of that worthless character, the 

 shape of the metatarsal tubercle. On trying to make use of their 

 comparative descriptions of Rana and Fyxicephalus one feels the 

 need of applying St. Jerome's dictum : " Major styli pars quae 

 delet quam qua? scribit." 



Text-figure 2. 



Skull of Rana adspersa. 



a. At about one year. 



b. ,, „ two years. 



e. „ „ three years. 



d. „ „ three years. 



Dorsal view. 

 Dorsal view. 

 Dorsal view. 

 Ventral view. 



(Nat. size.) 

 (Nat. size.) 

 (Nat. size.) 

 (Nat. size.) 



e. Skull of an old specimen. Dorsal view. (Half nat. size.) 



It seems probable that both species are derived from the 

 R. tigrina group of Rana, s. str., many points about the latter's 

 skull confirming this view *. 



* The proportions and positions of the nazals, fronto-parietals, and ethmoid j 

 length and strength of the zygomatic process of the squamosal ; lejigfb of the iawej" 

 limb of the pterygoid and its suture with the parasphenoid. 



