CHAP. XV.] THE PEDIGREE AND OlilGlN OF THE CAT. 515 



tnotli followed by one or more tubercular molars, but which, instead 

 of this, had a series of sectorial teeth. 



§ 6. It has been contended by several eminent palajontologists 

 that these creatures were marsupial, and that all the first mammals 

 were didelphous mammals — an opinion supported by the before 

 explained * resemblance of the mesozoic mammalian fossils to the 

 existing marsupial — Ilynnecohius. 



If this view is correct, the pedigree of the cat descends through 

 marsupial ancestors to the most generalized placental (or monodel- 

 phous) carnivora. It is here contended, however, that such was 

 not the case, but, on the contrary, that it is probable that the cat 

 never had a marsupial (or didelphous) ancestor at all, but that its 

 progenitors (anterior to carnivores) were long-lost beasts of the 

 Order Imectkora. It appears indeed to be probable that Insectivores 

 and not Marsupials "were the parent forms of the great INIammalian 

 stock — i.e., that the hedgehog and not the opossum is the existing 

 representative of the root-form of that class to which we (as 

 animals) and the cat both belong. 



Those characters in which Pterodon, Procivcrra, Hywnodon, Pake- 

 onictis, &c., have been thought to resemble marsupials, tell equally 

 in favour of their affinity to the Insectivora. Such are the small 

 brain, with uncovered corpora quadrigemina and large olfactory lobes 

 — characters which has been shown to have existed in Provicerraf 

 and Arctocijon.X Such again are the numerous sectorial teeth of 

 Hycenodon, Pterodon, Paheonictis, Provirerra and others, and the 

 defective palatal ossification of Arctocyon. Moreover these forms 

 do not possess more than six incisors above and below, while the 

 angle of the mandible is not inflected. If the angle were inflected, 

 however, such a character would not be decisive in favour of their 

 marsupial affinities, as the Taurec (Ceii fetes), though a placental 

 mammal — a member, moreover, of the order Insectivora — has 

 its mandibular angle inflected. Hycenodon and Pterodon have also 

 been shown § to have possessed a complete milk dentition, a character 

 which separates them markedly from all existing marsupials. 



To this reasoning it may be replied, that true marsupials existed 

 in Europe contemporaneously with the beasts the nature of which 

 is in dispute, and that the earliest known mammalian remains 

 (those of the secondary rocks) resemble existing marsupials. These 

 assertions are true, but in the first place the existence of marsupials, 

 with such creatures as Provirerra, only proves that marsupial life 

 was then already developed as well as placental life, a fact 

 of which we have] abundant evidence. || Such a fact, however, 

 in no way shows that the latter was derived from the former. 

 Then as to the mesozoic mammals, the forms now living which they 

 resemble, i.e., Myrmecohim, is just one of those marsupials to which 



* See ante, p. 504. 



+ See Les Enchainements, p. 21, fig. 

 15. 



J See P. Gervais, in Nouv. Archiv. 

 dn Museum, vol. vi., 1870, p. 147, plate 



6, fig. 4. 



§ By M.' Filliol, see Ann. des Sc. 

 Geologiques, vol. vii., p, 169, plate 22, 

 lig. 79, and plate 31, fig. 148, 1876. 



II See conk, p. 507. 



L L 2 



