68 



XXIII. ARCTOCYONIDAE. 



Extinct. 

 Arctocyon Blainv. -\-Palaeocyon Blainv. (not Lund). 



XXIV. HYAENODONTIDAE. 



Extinct. 

 Hyaenodon de Laiz & de Par.= ? Hyaenodon-\-Taxotherium-\-Pterodon Blainv. 



Fissipedium Genera incertae sedis. 

 Acanthodon Meyer. 

 Harpagodon Meyer. 

 Patriofelis Leidy. 

 Sinopa Leidy. 



(HyaenidaeF) 

 Lycyaena Hensel. 

 Hyaenictis Gaudry. 



(Fircmdae?) 

 Ictitherium Gaudry. 



PINNIPEDIA. 



FAMILIES. 



I. Molar teeth f or | : canines of both jaws moderately developed, those of 

 upper jaw being scarcely larger than those of lower; incisors persistent. 

 (Phocoidea.) 



A. Form comparatively archetypical, with the hinder legs flexible for- 

 wards. Small ear couchs developed. Skull with the mastoid processes 

 strong and salient, standing aloof from the auditory bullae ; with well- 

 developed post-orbital processes, and alisphenoid canals. Incisors (|) 

 of upper jaw notched. Anterior limbs about as large as the posterior; 

 their feet with digits decreasing in a curved line and without claws: 

 posterior feet with all their digits nearly co-terminal and furnished with 

 long linguiform flaps extending beyond their tips ; the three middle toes 



alone clawed. 



OTAEIIDAE. (XXV.) 



B. Form attypically phociform, with the hinder legs projected back- 

 wards and not flexible forwards. Ear conchs obsolete. Skull with the 

 mastoid processes swollen, and seeming to form part of the auditory 

 bullae; the post-orbital processes null or obsolete: no alisphenoid 

 canals. Incisors (variable in number | or f, or | ) of upper jaw not 

 notched. Anterior limbs smaller than the posterior; the feet with the 

 digits successively abbreviated and armed with claws ; the posterior 

 flippers emarginated (the third and fourth digits being shortest), and 



provided with claws (rarely suppressed). 



PHOCIDAE. (XXVI.) 



