1866.] DR. J. E. GRAY ON THE PTEROPINE DATS. 63 



my catalogue prepared more than twelve years ago, adding the de- 

 scriptions of the new species which have been received during that 

 period. I am aware that the best that can be done can only be an 

 essay, leaving much to be corrected and modified. 



Since I formerly worked on this group, a number of new species 

 have been described ; and M. Gervais, M. de Saussure, and Dr. Peters 

 have published excellent essays, describing the external form, the 

 skulls, dentition, and sometimes the skeletons of different species. 



I have great advantages for this undertaking. I have a very large 

 collection under my care, perhaps the largest yet formed in Europe, 

 containing many of the specimens on which species have been 

 founded by different English and foreign authors, those species 

 having been described from the specimens then in the British Mu- 

 seum, or since received from the different European museums. 



I can lay the whole series of the specimens of each genus or group 

 out before me and examine and compare them in detail, and repeat 

 the operation as often as I desire. I believe that no such exami- 

 nation of a large collection has been made since M. Geoffroy under- 

 took his series of monographs of different families of Mammalia in 

 the Paris Museum, shortly after Napoleon's accession ; and I have 

 the advantage of having a collection much more numerous ; indeed, 

 judging by the estimate of the Primates given in his ' Catalogue of 

 Primates,' it must be twice or nearly three times as numerous in 

 specimens as the Museum in Paris. 



I have made great progress in this catalogue, some specimens of 

 which have already been laid before the Society ; and the part con- 

 taining the Primates is now in the press, and I hope it will appear 

 in the course of this spring. I am aware that some zoologists will 

 complain that the characters are too short ; but short as they are, 

 they are the result of much study and analysis. They are the ciiarac- ' 

 ters that appear to me best suited to distinguish each species from 

 its allies, after a careful examination of a long suite of specimens of 

 each species placed side by side, and with its allies. 



It is a labour of love, and I hope to complete the examination and 

 description of the species of the class ; but at my age I have many 

 hindrances. I am fortunately greatly assisted in my study by my 

 excellent helper, Mr. Edward Gerrard, who has a very extensive 

 knowledge of the living and preserved specimens and their osteology ; 

 and his modesty is only equalled by his knowledge. 



The examination of the species of the Pteropidce has led me to 

 propose the following distribution of the genera, which may be thus 

 characterized : — 



I. Teeth 34 ; true grinders 3/3 ; hinder small ; false grinders 

 2/3 or 2/2 ; front small, and often deciduous. 



1 . Cutting-teeth 4/4 „■ lower in a regular series. Tail none. Gland 

 of the penis bony. Pteropina. 



1. Ptekopus. Wings from the sides of the hairy back. P.me- 

 dius. 



