576 ON REMAINS OF A THERIODONT REPTILE. [NoV, 19, 



from the humerus of Brithopus in that the postasial aperture of 

 the entepicondylar foramen is situated on the palmar instead of the 

 postaxial border of the hone ; but this is due to the imperfection of 

 the latter border in the type of Brithopus. 



Having now described those of the associated series of bones which 

 appear best worthy of notice, it remains to consider whether they can 

 be referred to any form hitherto described. In cases like the present 

 where, from the want of homologous portions of the skeleton, there 

 is no decisive evidence as to whether specimens can be referred to a 

 previously described form, by far the easiest and simplest course is 

 to make their owner the type of a new genus. As a rule, however, 

 this very easy course turns out to be an erroneous one, and it is 

 therefore not the one which I propose to follow on this occasion. 



If, as seems to be the case, the humerus represented in plate xix. 

 fig. 1, of Owen's ' Catalogue,' is rightly referred to Cynodraco major 

 — the largest of the typical Theriodontia — it is quite clear, from the 

 larger size and different contour of the humerus, that the present 

 series of specimens cannot be referred to that restricted group, which 

 may be conveniently designated as the Galesauridce. Moreover, 

 although we have no decisive evidence of the nature of the vertebrae 

 in the Galesauridce, yet there are some reasons for considering that 

 these were not of the notochordal type of the present form. Again, 

 it is quite clear that these specimens indicate a Theriodont which is 

 generically distinct from the large types described under the names 

 of I'apinocephalus, Titanosuchus, and Pariasaurus, the vertebrae and 

 humeri which appear to be referable to the two former genera being 

 greatly larger and differing in contour from those of the present 

 series. 



Recently, indeed. Professor Seeley ' has described and figured a 

 large imperfect tooth from the Karoo system of the Cape preserved 

 in the British Museum (No. 49425) under the name of Glaridodon ; 

 but there is nothing by which this specimen can be generically 

 distinguished from the teeth of Titanosuchus', so that Glaridodon 

 may be a synonym of that genus. 



There is not sufficient evidence to show that the form under con- 

 sideration does not belong to the Permian Brithopus, and I there- 

 fore refrain from giving it a new name. Additional evidence of its 

 affinity to that form is afforded by the vertebrse figured in Eichwald's 

 ' Lethsea Rossica,' pi. lix. figs. I, 2, and described as Deuterosaurus. 

 These vertebrse are smaller than those of our series, but appear to be 

 of the same general type, showing similar long transverse pro- 

 cesses, a sharp haemal carina to the centra, and the shortening of 

 the latter in the lumbar region. These vertebrae, judging from the 

 present series, are too small to have belonged to the same individual 

 as the type of Brithopus, but may indicate a smaller example of the 

 same genus. So far, indeed, as I can see, there is no reason why 



^ Proc. Eoy. Soc. vol. xliv. p. 135 (1888). In the absence of any specific 

 name the genus is invaUd. 



^ The tooth described as Glaridodon has been recently cut in order to 

 exhibit a section of the root. 



