the Primates, as to render a perfect "monograph" of the Order possible. Dr. Forbes has endeavoured in these volumes to bring the subject up to date, and has devoted some years of study to the two which now appear under his name, and he has had the great advantage of having seen many of the species of which these volumes treat, in a state of nature. If diligent research and patient work, combined with a sound anatomical knowledge and an acquaintance with many species of Monkeys in their natural habitat, avail anything, then these volumes should present to the student a more concise epitome of the characteristics of the Primates than any other essay yet offered to the public. It has been found impossible to reproduce any of the plates in the old "Naturalist's Library" of Jardine. They would have formed, with appropriate inscriptions, a very good instalment of a series of "Comic Natural History" volumes, as they were, in fact, nothing but a set of extraordinary caricatures of Monkeys. I have, therefore, again to acknowledge the liberality of the publishers, in adopting my suggestion that a perfectly new set of illustrations should be prepared. These have been executed by Mr. J. G. Keulemans, with a result, I hope, that will satisfy the reader. R. BOWDLER SHARPE. INTRODUCTION. In the first volume will be found an account of the _Lemuroidea_, and the _Anthropoidea_ as far as the group of the Macaques of the family _Cercopithecidæ_. The second volume continues with the latter genus, and contains the rest of the Monkeys, and the Apes, as well as a summary of the geographical distribution of the species of the Order Primates. I have not attempted to write a complete synonymy of the species of Monkeys. The literature is scattered over many, often obscure, periodicals, and without seeing the actual specimens described by some of the older writers, it would be easy to introduce a great deal of confusion into the synonymy. I have, therefore, only attempted to give the principal references. I must express my obligation to Dr. Günther, F.R.S., the Keeper of the Zoological Department in the British Museum, for the facilities of study afforded to me in that institution. To Mr. Oldfield Thomas I am likewise greatly indebted for much assistance, and for many a kindly hint. Dr. Forsyth Major, who is well-known as one of the foremost authorities on the Lemurs, not only gave me valuable information as to the species and literature of the _Lemuroidea_, but was even so good as to furnish me with the descriptions of several new species. Lastly, to my friend the Editor, I have to return my sincere thanks for the patience with which he has revised my MSS., and for the verification of numbers of references, only to be found in the great libraries of London, and inaccessible to an author dwelling in the provinces. HENRY O. FORBES. SYSTEMATIC INDEX. PAGE ORDER PRIMATES 1 SUB-ORDER I. LEMUROIDEA 8 FAMILY I. CHIROMYIDÆ 14 I. CHIROMYS, Cuvier 14 1. madagascariensis (Gm.) 14 FAMILY II. TARSIIDÆ 18 I. TARSIUS, Storr. 18 1. tarsius (Erxl.) 20, 286 2. fuscus, Fischer 21 FAMILY III. LEMURIDÆ 22 SUB-FAMILY I. LORISINÆ 24 I. PERODICTICUS, Bennett 26 1. calabarensis, Smith 27 2. potto (Geoffr.) 28 II. LORIS, Geoffr. 31 1. gracilis, Geoffr. 31 III. NYCTICEBUS, Geoffr. 33 1. tardigradus (Linn.) 33, 286 SUB-FAMILY II. GALAGINÆ 37 I. GALAGO, Geoffr. 38 1. garnetti (Ogilby) 40 2. senegalensis, Geoffr. 41 3. alleni, Waterh. 43 4. demidoffi, Fischer 44 5. monteiri, Bartlett 46 6. crassicaudata, Geoffr. 47 II. CHIROGALE, Geoffr. 49 1. milii,...