SEAL-EMBRYOS. 11 
terrestrial Carnivora as given by Drs. Parsons and Windle (14), to see what evidence, 
if any, could be obtained in support of Mivart’s suggestion that the Otaries may have 
been derived from bear-like ancestors, while the Phocide had another, possibly Lutrine 
origin (8). 
From the fact that the muscles which show distinctive characters between the 
Urside and the Mustelidz are with one exception (viz. the Rhomboideus profundus as 
a separate muscle) confined to the limbs, the very positions in which adaptive 
peculiarities would probably be most apparent, it might be inferred that but little 
evidence would be forthcoming from this source. As a fact, however, the altered 
position and functions of the limbs seem to have produced, at least in the embryo, 
comparatively little change in the muscular attachments. 
Anterior extremity.—(i.) The Supinator longus is a well-marked muscle inserted 
into the lower end of the radius. It arises from high up on the shaft of the humerus 
close to the tuberosities, there being practically no origin from the supra-condylar 
ridge. The origin of the muscle agrees closely with that of Trichechus, but would 
appear to correspond only with the second additional belly arising from the deltoid 
ridge which Dr. Murie described in Osaria jubata. The attachments also further 
correspond with those found in Lutra. According to Drs. Parsons and Windle this 
muscle is constantly present in the Urside, Viverride and in most of the Felide, but 
absent in the Canide and Hyzxnde. 
(ii.) The Pronator radi teres is inserted into quite the lower end of the radius, 
and I could find no deep head of origin. This attachment agrees with what 
Drs. Parsons and Windle found throughout the land Carnivores, and they point out 
that the insertion is ‘“ of some interest from a systematic point of view.” The insertion 
found in the seal agrees with that found in the Urside and many Mustelide, including 
Lutra vulgaris. The description given by Dr. Murie in Otaria is rather ambiguous, 
but the attachments would seem to be more extensive, though it must be remembered 
that he is describing the conditions found in the adult animal, and it is quite possible 
that in the seals the terrestrial condition found in the foetus may, when the limb 
becomes functionally powerful, give place to more extensive bony attachments. 
(iii.) Flexor carpi radialis is inserted into the bases of the first and second 
metacarpals, the latter attachment being the smaller, and has disappeared altogether 
in Otaria. The insertion. into both metacarpals agrees with the condition found by 
Meckel in Ursus arctos. 
(iv.) Palmaris longus.—The attachments of this muscle appear to vary considerably 
in the land Carnivora. Drs. Parsons and Windle describe this muscle as composed 
of external and internal portions, both of which are present in the Procyonide alone, 
the muscle being frequently absent altogether in the Ursidx. They find both portions 
of the muscle present in Lutra cinerea, while in the majority of the Mustelide, 
including L. vulgaris, the large external one alone was present. Both portions are 
present in the embryo seal, the external being the larger. The condition approximates 
C2 
