522 Reviews—Sir EH. Ray Lankester on the Okapi. 
REVIEWS. 
I.—MonoarapH oF THE Oxapr—Arras. By Sir E. Ray Lanxester, 
K.C.B., M.A., D.Sc., F.R.S. Compiled with the assistance of 
W. G. Rivewoop, D.Sc. 48 plates. 4to. Printed by order of 
the Trustees. Price 25s. 
a CE its discovery some ten years ago, the Okapi has perhaps 
been the subject of more papers and memoirs than have ever 
been devoted to any Ungulate mammal not of actual econdmic 
importance. The circumstances of its discovery, its isolation from 
other living forms, and its near relationship to Pal@otragus and 
Samotherium of the Lower Pliocene of Greece have all excited 
general interest in it. An important addition to the publications 
referring to this animal has just been issued by the Trustees of 
the British Museum under the title A Monograph of the Okapi— 
Atlas. This volume consists of a series of forty-eight plates pre- 
pared under the direction of Sir E. Ray Lankester, in illustration 
of a complete account intended to be prepared by him. These 
illustrations are of especial value because they bring together figures 
of the skulls and skins of a considerable number of individuals, 
including not only those in the British Museum, but also several 
from foreign museums and private collections. One set of plates 
consists of a beautiful series of drawings of the skulls of a number 
of individuals, illustrating the great variability of this part of the 
skeleton and of the degree of ossification of the curious separate 
horn-cores or ossicones, which in one set of individuals are entirely 
absent. A number of other plates show some of the remarkable 
peculiarities in the structure of the vertebre, particularly in the 
cervical region, and finally some ten plates are devoted to demonstrating 
the extreme variability of the striping on the fore and hind legs, 
and incidentally prove the futility of naming new species on the 
evidence of such unstable characters. It is much to be regretted 
that, according to the preface, the volume of text relating to these 
plates will probably not be published: at the same time the recent 
publication of several important memoirs on the subject renders this 
omission less serious, and the detailed and careful descriptions of the 
plates prepared by Dr. W. G. Ridewood add greatly to the value of 
the volume and go far to reconcile us to the absence of the text. 
The plates are for the most part drawn by Miss G. M. Woodward and 
Mr. Gronvald. 
IJ.—orran Deposits. 
[ Alexandra Ivchenko’s papers (in Russian, with abstract in French) 
will be found, illustrated, in Khrishtafovich’s Hzheiodnika no Gheol. 
¢ Min. Rossii (Ann. géol. et min. Russie), xii, pp. 146-70, 1909. ] 
A GOOD deal has been written lately on Deserts in one form or 
another, and we think it may be interesting to give a résumé of 
the views of Alexandra Ivchenko (or as he transliterates his name 
into French, Iwtschenko) of Kiev. Mr. Ivchenko finds that the types 
a 
