CHAP, xv.] THE PEDIGEEE AND ORIGIN OF THE CAT. 617 



than that the allantois should first appear as a functionless rudi- 

 ment. It also seems more probable that the habit of forming milk 

 teeth is one which has been lost or almost lost in certain mammals, 

 than that the process should first have arisen through the replace- 

 ment of a single, relatively unimportant, tooth, by a vertical successor 

 to it a condition which has been found* to be the case in the 

 marsupials of our own day. 



; 7. The succession of mammalian carnivorous life the mammalian 

 portion of the CAT'S PEDIGREE may then be represented as follows : 



From unknown Insectivora-like mammals, two diverging series of 

 forms may have started, one soon leading to Arctocyon (as the 

 Insectivora-like root of the placental Carnivora), the other series 

 developing such forms as Proviverra, Hycenodon, and Pterodon, and 

 continuing on the main stem through Gymnura-like creatures to the 

 modern Inscctivora. From this insectivorous stem we may imagine 

 a side-shoot to be given off leading through Palceonictis to forms 

 like certain existing marsupials, and diverging into the American 

 Didelphys and the analogous Australian Dasyurus. From Arctocyon 

 we may conceive the great carnivorous branch destined to quite 

 surpass and overshadow the insectivorous stem to divide into 

 cynoid and arctoid branches. The former continuing on through 

 Cynodon and Cynodictis, would lead up through Galecynm and 

 forms like the existing Otocyon to the typical Canidcs. The great 

 arctoid branch may have given off a limb leading through Amphicyon, 

 Hycenarctos and kindred forms, to the existing Ursidce, and then 

 continued on through Procelurus and -Lutrictis, as the Mustelidce. 

 From some such form as Procelurus the great ^Eluroid sub-order 

 may have started, and before continuing on, as the Viverridce, have 

 given off a great branch to be developed, by bifurcating, into the 

 HycBniddByCryptoproctidcB and jFWfcp. The first family is the culmina- 

 tion of one division which passes through Ictitherium, and which 

 gives off Proteles as a one-sided branchlet. The other division into 

 which the ^Eluroid branch bifurcates, continues on as the cats, first 

 giving off however, near the bifurcation, the branchlet ending in 

 Cryptoprocta. The proper feline branch then continues on through 

 Archcelurus, Dinictis, Nimravus and Pseudcelums, and then bifurcates. 

 It ends in the typical genus Felis on one side an aberrant twig 

 being given off for Cyncelurus while on the other side it continues 

 on though Hoplophoneus, Pogonodon and Machcerodm f to the very 

 specialized aberrant form Eusmilus. ^ 



This hypothetical genealogy is only offered as a speculation, especi- 

 ally that part of it which represents conditions anterior to the evolution 

 of the viverrine branch. It reposes mainly upon dental characters, 

 and teeth are organs which not only might be expected to vary with 



* By Professor Flower. See his paper 

 in the Philosophical Transactions, vol. 

 civil., 1867, p. 631. 



t The small lamina of bone which em- 

 braces the external carotid and so forms 



the " ali-sphenoid canal" may well have 

 independently disappeared and again, by 

 reversion, reappeared in either sub- 

 division of the feline branch. 



