PEEFACE 



The hope was expressed, in the Preface to the previous 

 Volume, that it mighc be possible to issue a fifth, or 

 concluding Volume, without undue delay. That hope has 

 been realised, as tlie result of finding the materials for the 

 completion of the work among the papers of the late 

 Mr. Eichard Lydekker. 



The volume now published is practically as the author 

 left it, and the only alterations that have been made are 

 verbal ones. Even the illustrations are those which he had 

 himself selected. 



It will 1)6 obvious, however, that this volume sliould not 

 be regarded as a finished production. The earlier part is 

 drawn up on the general lines of the preceding volumes, 

 and contains lists of the specimens in the collection. These 

 do not appear in the second half of the volume, which 

 consists mainly of a list of species and subspecies, with 

 synonymy and indications of the typical localities. The 

 manuscript was, indeed, in the condition of a preliminary 

 draft, and readers should bear in mind that it has not had 

 the advantage of being amplified and revised by the author. 



On the other hand, it has not been thought advisable to 

 make any attempt to complete the volume on the full 

 original plan, partly on account of the difficulty of finding 

 anyone competent to do so, and partly because the mixed 

 I'esponsibility for the woi'k which would be thereby intro- 

 duced would not be for the benefit of science. 



The thanks of the Trustees are due to Messrs. George 

 Allen & Unwin, Ltd., for permission to use certain copyright 

 figures published in Mr. Lydekker's work, Tlie Horse and its 

 Relatives; to Lord Kothschild, F.E.S., for the use of figures 

 from the Notitatcs Zoolor/icce ; and to tlie Zoological Society 



