1y PREFACE, 
In these works, however, there is great divergence as to the 
classification and nomenelature of the specimens, Dr. Gray, especi- 
ally after he had commenced to study the configuration of the 
skulls, having introduced at successive periods numerous changes 
which cannot be maintained in the present state of our knowledge. 
Also the ‘ Hand-List’ of 1873 has become antiquated, not only on 
account of the additions of more recent years, but also in consequence 
of the elimination of numerous duplicates which were transferred to 
other public Museums. 
Thus it appeared desirable to prepare another issue of this 
‘ Catalogue’ on the plan of the new series of descriptive Catalogues 
of the Zoological Collections. Numerous woodcuts have been 
introduced, chiefly with the object of illustrating the principles 
adopted in the classification; all are taken from specimens in the 
Museum, but many have already appeared in Dr. Gray’s papers in 
the ‘Proceedings of the Zoological Society,’ and are reproduced 
here by the kind permission of the Council of that Society. 
ALBERT GUNTHER, 
Keeper of the Department of Zoology. 
British Museum (N. H.), 
January 13, 1889, 
