374 
semblance of consistency. Neither have the paleonto- 
Jogists been idle during the period referred to, the wonder- 
ful extinct mammalian fauna of Patagonia—inclusive of 
the ground-sloth, whose skin was recently found in a 
cave at Ultima Esperanza—having been to a large 
extent described during the last decade, while many 
interesting forms of extinct mammalian life have been 
made known from other parts of the world. If to the 
above be added the change of view with regard to the 
limits of zoological regions and the extent to which lands 
now widely sundered have been connected in past 
epochs of the world’s history, there is little cause for 
wonder if the majority, or all, of the standard text-books 
dealing with mammals are more or less completely out 
of date. 
Accordingly, it may be taken for granted that a trust- 
worthy and up-to-date technical text-book on the study 
of mammals is a desideratum at the present time, and 
that the author has thus an unusually favourable oppor- 
tunity before him. But this is not all that may be said 
in his favour, apart from the contents of the work itself. 
Mr. Beddard, from his official position at the Zoological 
Society’s Gardens in the Regent’s Park, has special, and 
probably unrivalled, opportunities of making himself 
acquainted with the anatomy ofthe soft parts of mammals 
—a subject too often neglected, or treated in insufficient 
detail in works of this nature In addition to devoting a 
large amount of attention to the external glands of 
mammals, as well as to their internal anatomy in general, 
Mr. Beddard has made a special study of the mammalian 
brain, the results of which are incorporated in the volume 
before us. On this, if on no other, account his work 
must have an exceptionally high value for the students 
of mammals, as containing an enormous amount of 
information on this branch of the subject which can be 
obtained elsewhere only by laboriously searching through 
a long series of original memoirs. 
NATURE 
A special feature of the volume is the large amount of | 
space devoted to the consideration of extinct forms of 
mammalian life; and this is the more to the author’s 
credit since, we believe, he is not himself a student of 
the palzeontological aspect of the subject. He has, how- 
ever, doubtless realised that the extinct forms afford the 
only key to the true relationship of their modern 
descendants ; and he is to be congratulated that his 
work stands apart from all text-books on the same 
subject published in this country on account of the large 
amount of detailed information concerning extinct types. 
For one who is not himself a paleontologist, the author 
appears to have succeeded remarkably well in the treat- 
ment of this portion of the subject. He has, however, 
unfortunately quite failed to realise the nature of the 
dental succession in elephants and mastodons. Other- 
wise we should not have met with the statement on 
p. 220 that Avephas planifrons is the only member of its 
kind in which milk-molars are developed, and that in 
mastodons these teeth are more ESTO | ; or the further 
and contradictory statement on p. 230 that these teeth 
occasionally persist throughout lifes He should, of 
course, have known that milk-molars are always present, 
and that in one elephant and several mastodons they are 
succeeded by pre-molars. 
As regards zoological regions, it 1s satisfactory to find 
that Mr. Beddard has adopted the view that the land 
surface of the globe is divisible, from this point of view, 
into three primary divisions, or realms, at least one of | 
which is capable of being split up into regions. The 
division of the northern part of Arctogzea into a pale- 
arctic and a nearctic region is, however, retained ; and it 
is somewhat regrettable to find that the author is unable 
to convince himself of the necessity of a Sonoran region. 
Even greater matter for regret is his refusal to 
allow the rank of a region to Madagascar. Still, of 
course, the author has a perfect right to his own opinion, 
NO. 1711, VOL. 66] 
| true placentals. 
[AucustT 14, 1902 
and cannot be condemned for following the same. In 
the introductory chapters a noticeable feature is the 
large amount of space allotted to the consideration of 
the structure and development of the milk-glands of 
mammals, in the course of which the author takes 
occasion to refer to the remarkable circumstance that 
the egg-pouch of the monotremes does not appear to be 
homologous with the nursing-pouch of the marsupials. 
Hair-glands are likewise discussed at some length, some 
countenance being given by the author to Dr. Weber’s 
theory that the ancestral mammals were scaly creatures. 
Teeth, as might have been expected, receive a large 
share of attention in the same section of the work, their 
cusps being named on the American system based 
on ‘‘trituberculism.” Speaking generally, the author’s 
treatment of the difficult subject of dentition is decidedly 
good ; we believe, however, that on p. 48 he has written 
fifty-four in place of forty-four as the normal maximum 
number of mammalian teeth, while he has omitted to 
mention that the replaced tooth in marsupials, which he 
identifies with the last premolar, has been regarded by 
at least one recent writer as corresponding with the 
From Beddard’s 
Fic. 1.—A Flying Fox (2. Leropus poliocephalus). 
“Mammalia.” 
third of that series. Allusion is made to the mammalian 
resemblances of the dentition of the African Anomodontia 
(a group-name which, by the way, the author, on p. 48, 
credits to Huxley instead of Owen), but the question 
whether the one type is directly derived from the other 
is not discussed. 
Passing from the introductory to the systematic portion 
of the work, we find Mr. Beddard differing from the 
majority of his predecessors in dividing the Mammalia 
into two, in place of three, primary groups—namely, the 
Prototheria, now represented only by the monotremes, 
and the Eutheria, including both marsupials and the 
In view of the discovery of a vestigial 
placentation in marsupials, to which allusion has been 
already made, as well as from other considerations, we 
are inclined to think that the author is fully justified in 
the innovation, and hope to see the new departure 
followed by other writers. The absence of a corpus 
callosum in the brain of monotremes is regarded by the 
