Marsh Collection, Peabody Museum. 127 



turing its prey and its habits of feeding were not analogous 

 nor similar to those of the cats, since the evidence positively for- 

 bids the idea of any prehensile powers of the claws, one of the 

 most preeminently distinguishing features of the Felidse in this 

 respect ; and (5) that it was likewise not similar to that of the 

 dogs, for the structure of the limbs disproves the suggestion of 

 a runner. 



What osteological character or characters do the living 

 aquatic Carnivora possess, by means of which their habits 

 could be detected if known from their skeletons alone ? The 

 various degrees of modification for a swimming habit are pro- 

 gressively shown by such types as the mink, otter, sea-otter, sea- 

 lion, and seal. The mink and otter are semi-aquatic, the sea-otter 

 more aquatic, and the sea-lion and seal almost' exclusively so. 

 The limbs, and especially the feet, exhibit the greatest amount 

 of modification of any parts of the skeleton and the degree of 

 this modification is proportioned to the extent of the aquatic 

 habit. In cases of extreme specialization, as in the sea-lion and 

 seal, the fore and hind feet are almost equally modified, but in 

 such an example as the sea-otter, it is only the hind feet that 

 show any considerable adaptive changes of this character. 

 This is also true of the mink and otter, but in these types the 

 difference between the fore and hind feet is not so great. 



It is for this reason that I limit what I shall have to say to a 

 consideration of the posterior limbs ; and it should be noted 

 that all these aquatic or semi-aquatic species are plantigrade in 

 gait when upon land, that the metatarsals are short and little 

 interlocking, and that the toes are spreading. Taking the foot 

 of the sea-lion as an extreme type, it will be seen that when 

 placed with the plantar surface upon the ground, in the direc- 

 tion of the long axis of the body, the articular surface for the 

 tibia looks upwards and very much inwards, so that if the tibia 

 is articulated it does not occupy a vertical position as in the 

 terrestrial species, but leans very much inwards towards the 

 median line. If made to assume a vertical position the plantar 

 surface of the foot is turned strongly inwards; At the same 

 time the tibia is twisted in such a way that the fore and aft 

 planes of the articular faces of the two ends do not coincide. 

 These characters in connection with the elongation of the pha- 

 langes constitute the chief peculiarities of the hind limbs of the 

 aquatic Carnivora, and, as far as known, are present in all of them. 

 With the exception of the elongation of the phalanges, Patrio- 

 felis exhibits these identical characteristics of the hind li mbs, and 

 if they have any significance at all, they indicate an aquatic or 

 partially aquatic habit of the species. I have yet to discover 

 any evidence which opposes itself to the correctness of this view. 



I have suggested that the animal preyed upon the numerous 



