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Show 576 ON REMAINS OF A THERIODONT REPTILE. [NOV. 19, from the humerus of Brithopus in that the postaxial aperture of the entepicondylar foramen is situated on the palmar instead of the postaxial border of the bone; 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 Galesauridee. Moreover, although we have no decisive evidence of the nature of the vertebrse in the Galesauridee, 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 Tapinocephalus, Titanosuchus, and Pariasaurus, the vertebrse and humeri which appear to be referable to tbe 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 Titanosuchus2, so that Glaridodon may be a synonym of that genus. There is not sufficient evidence to show that the form under consideration does not belong to the Permian Brithopus, and I therefore 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. 1, 2, and described as Deuterosaurus. These vertebrae are smaller than those of our series, but appear to be of the same general type, showing similar long transverse processes, a sharp hsemal carina to the centra, and the shortening of the latter in the lumbar region. These vertebrse, 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 1 Proc. Eoy. Soc. vol. xliv. p. 135 (1888). In tbe absence of any specific name tbe genus is invalid. 2 Tbe tootb described as Glaridodon bas been recently cut in order to exhibit a section of tbe root. |