60 POPULAR SCIENCE REVIEW. 
cases, a far wider distribution than can generally be enjoyed by terrestrial 
mammals ; and hence Mr. Allen’s investigations, although specially directed 
to the species inhabiting the shores of North America, necessarily range 
over a far more extended field, and deal with forms in which European 
naturalists have a direct local interest. Moreover, in discussing systematic 
points, questions of nomenclature, &c., our author does not confine himself 
to the species with which he has specially to deal, but treats of the group 
generally, referring also to the habits and natural history of species from 
all parts of the world, and thus his book is rendered indispensably necessary 
to every student of the Pinnipedia. 
In the classification of the Pinnipeds the author introduces one new 
feature : he divides the sub-order into two great tribes, — one including the 
Eared Seals and Walruses, which have their hind feet turned forwards and 
walk upon all fours, which he calls Gressigrada ; the other for the reception 
of the ordinary seals, which progress on land by the action of their fore- 
paws alone, assisted by wriggling motions of the body, and these are accord- 
ingly named Reptigrada. The groups seem to be natural enough, but we 
don’t admire their names. 
At the outset the reader is somewhat startled at missing the old familiar 
name of Tnchechus for the Walrus, and finding substituted for it the very 
unfamiliar one of Odobcenus. There is no doubt that it was by an incon- 
ceivable series of blunders that Linnaeus, in the last edition of his Sy sterna 
Natures, transferred the Walrus to the genus Trichechus, which belongs of 
right to the Manatee ; but we question whether under the circumstances it 
was worth while to disturb the existing nomenclature. Mr. Allen dis- 
tinguishes two species of Walrus, — the Atlantic Walrus ( Odobcenus 
ro&mai'us ) and the Pacific Walrus (O. obesus ), — and a very full account is 
given of their characters and natural history. Copies of the very curious 
old figures of the Walrus, taken from the late Dr. Gray’s paper in the Pro- 
ceedings of the Zoological Society (1853), show rather amusingly how very 
far the vivid imaginations of travellers and naturalists could carry them. 
Mr. Allen discusses at considerable length the difficult question of the 
species of Eared Seals (Otariidae), and comes to the conclusion that all the 
known forms may be referred to nine species, — five of which are Hairy 
Seals, or Sea-Lions (forming the sub-family, Trichophocaceae), and four of 
them Fur Seals, or Sea Bears (Ouliphocaceae). The general natural history 
of these animals is given in some detail, with a tabular synopsis of the 
genera and species, and the three species (two Sea Lions and one Sea Bear) 
which inhabit the Pacific coast of North America, are fully described from 
all points of view. 
The Earless Seals (Reptigrada) form the single family Phocidse, of 
which seventeen species are here catalogued by Mr. Allen, eight of them 
being fully described as inhabitants of North America. Besides these a 
ninth, somewhat doubtful species is noted as an inhabitant of the West 
Indies, and an occasional visitor to the southern shores of the United States. 
This seal ( Monachus ? tropicalis) appears to be known to the author chiefly 
from the descriptions of Hill and Gosse, who observed it in Jamaica. 
Here, as indeed throughout the book, Mr. Allen has devoted the most 
unwearied labour to the accumulation of reliable information, not only with 
