XIV ORIGIN OF MARINE CARNIVORA 449 
terrestrial Carnivora, but the question is, to which group of 
Carnivora have they the most likeness. The semiaquatic Otter, 
and the still more thoroughly aquatic (marine) Enhydris, 
suggest an affinity in that direction. The long body and short 
legs of the Otter, which is more thoroughly at home pursuing 
fish in the streams than in waddling clumsily upon the banks 
of the streams, seem to require but little external change 
to convert it into a small Seal, while the long and completely 
webbed hind digits of Hnhydris are even more lke those of a 
Pinniped. The Sea-Lions, in which thé external ear has been 
preserved, and in which the limbs have not become so entirely 
useless for progression on the land as they have in the Seals, 
seem to be the intermediate step in the evolution of the latter. 
This, however, is not the opinion of Dr. Mivart, who, without 
detinitely committing himself on the point, presents some evidence 
for the assumption that the marine Carnivora are diphyletiec. 
This double origin, however, is not from two groups of the 
terrestrial Carnivora. Dr. Mivart, in common with many others, 
holds that the Pinnipedia as a whole are undoubtedly nearer to 
the Arctoidea than to either of the two remaining sections of 
the sub-order. One of the most striking structural characters 
in which they show this resemblance is the brain; the peculiar 
Ursine lozenge, already treated of as so distinctive a character of 
the Arctoidea, is repeated in the Pinnipedia. 
There are, however, other points of likeness which seem rather 
to point to a Creodont origin. Patriofelis is a genus that from 
more than one side may be looked upon as a possible ancestor of 
these animals. The Creodont peculiarity of the vertebrae has 
already been referred to. It may be added that the facial part 
of the skull is small in Patriofelis, which appears, moreover, to 
have had an alisphenoid canal. A very remarkable resemblance 
hes in the structure of the astragalus. This is not deeply 
grooved on the tibial facet as it is in Fissiped Carnivora. This 
might be held to be an instance of degeneration in the aquatic Seals, 
which do not.use their limbs as walking organs. But Professor 
Wortman ' has pointed out that in the Sea-Otter, which is entirely 
aquatic, the groove exists and is plain. The likeness offered to 
the Seals by the spreading feet of Patriofelis is noticed under the 
description of that genus.” 
1 Bull. Amer. Mus. Nat. Hist. vi. 1894, p. 129. 2 P. 456 below. 
VOL. X 2G 
