AND ON 2ELTTR0SATJEUS FELIXTTS. 



265 



of Gorgonops * is narrow ; but the ordinal characters are manifest 

 in all ; only in the dwarfer and weaker species the relative size of the 

 canines decreases, as is the case with similar carnivorous Mammals. 



Qalesaurus planiceps and yElurosaurus felinus form an equal-sized 

 pair of these ancient Triassic precursors of our existing cats, or rather 

 cat-like Marsupials. Qalesaurus had tzf upper incisors like Dasy- 

 urus ; JElurosaurus had 5 ~ 5 upper incisors like Didelphys ; but the 

 molars of the foregoing and other Theriodonts indicate the lower or 

 earlier type that bore them in their simple acuminate form as in the 

 antecedent teeth ; they had not advanced to the more complex modi- 

 fied character shown in the molars of the most carnivorous of either 

 marsupial or placental Ferae. Galesaurus had as many as of 

 such molars ; in JElurosaurus they did not exceed, or at most by 

 one, the manifest in the fossil here described. 



Galesaurus, in the subject of the paper in the 16th volume of 

 our ' Quarterly Journal,' still has the advantage over all the subse- 

 quently discovered Theriodonts in the entireness of the skull, espe- 

 cially in the occipital region ; and we may infer, analogically, a 

 repetition of the reptilian characters of the cranium, indicative of 

 low cerebral development, in its coordinates. 



If we next compare JElurosaurus with the skull of Lycosaurus 

 curvimola f , which, at the date of its extrication, was the next in 

 completeness to that of Galesaurus, we find the nearer affinity to 

 JElurosaurus in the small number of molars, in the general propor- 

 tions of the skull, and in the extent and slope of the symphysis 

 mandibulee ; but the incisor-formula is Dasyurine, and the facial 

 part of the septum narium is prominently manifested. But, of all 

 the previously described genera of Theriodontia I deem I/ycosaurus 

 to have had the nearest kinship to JElurosaurus. 



I am indebted to Sir Bartle Frere, K.C.B,, for kindly taking 

 charge of, and placing in my hands, the unique subject of the 

 present paper J. 



EXPLANATION OF PLATE IX. 



JElurosaurus felinus. 



(All the figures are of the natural size.) 



Fig. 1. Right side view of the skull. 



2. Left side view of the skull. 



3. Under view of the skull. 



* Catalogue,?^ supra, p. 27, pi. xxi. t Ibid. p. 71, pi. 78. 



\ For the discussion on this paper, see p. 270. 



