CAKNIVORA. 889 



has extended. Garrod^ has pointed out the significance of the number of 

 convolutions of the middle and posterior part of the hemispheres. I have 

 added some characters derived from the foramina of the posterior and lateral 

 walls of the skull.- Mr. Turner also defines the families by the form and 

 relations of the paroccipital process. 



In studying the extinct Carnivora of the Tertiary period it has become 

 necessary to examine into the above definitions, in order to determine the 

 affinities of the numerous genera which have been discovered. To take 

 them up in order, I begin with the foramina at the base of the skull. The 

 result of my study of these has been that their importance was not over- 

 rated by Mr. Turner, and that the divisions of secondary rank indicated by 

 them are well founded. Secondly, as to the form and structure of the 

 auditory bulla. Although the degree and form of inflation are characteristic 

 of various groups of Carnivora, they cannot be used in a systematic sense, 

 because, like all characters of proportion merely, there is no way of express- 

 ing them in a tangible form. For, if the forms in question pass into each 

 other, the gradations are insensible, and not sensible, as is the case with an 

 organ composed of distinct parts. The same objection does not apply so 

 much to the arrangement of the septa of the bulla. The septum is absent 

 in the Arctoidea of Flower {Ursidce of Turner), small in the Cynoidea 

 (Flower, Canidce Turner), and generally large in the ^luroidea (Flower, 

 FelidcB Turner). But here occurs the serious discrepancy, that in the 

 Hysenidge, otherwise so nearly allied to the Felidse, the septum of the bulla 

 is wanting. Nevertheless, the serial arrangement of the order indicated by 

 Flower, viz, commencing with the Arctoidea, following with the Cynoidea, 

 and ending with the ^Eluroidea, is generally sustained by the structure of 

 the auditory bulla, and by the characters of the feet and dentition, as well 

 as of the cranial foramiua. Turner's arrangement in the order Ursidse, 

 Felidae, and Canidse is not sustained by his own charactei-s, and its only 

 support is derived from Flower's observations on the external or sylvian 

 convolution of the hemisphere of the brain.^ There are three simple longi- 



' Proceedings Zool. Soc, London, 1878, p. 377. 

 *Proceediug8 Amer. Philosophical Society, 1830. 

 "Proceedings Zoological Society, London, 1869, p. 482. 



