858 THE ZOOLOGIST. 
identify specimens either from their external characters or from 
the skulls alone. The introductory remarks on dentition, and 
upon the method of measurement adopted by the author, are well 
considered, and deserve careful perusal. 
In striking contrast with what has occurred in other groups 
of Vertebrates, the increase of known species of Cheloniangs, 
says Mr. Boulenger, “‘ has been very slight within the last well 
years.” In fact Mr. Boulenger’s Catalogue contains a much 
smaller number of species than did the late Dr. Gray’s 
‘Supplement’ to his ‘Catalogue of Shield Reptiles,’ published 
in 1870. This, no doubt, is due to the different views held by 
the writers as to what ought to constitute specific characters, and 
partly also to a better understanding at the present day of the 
amount of variation to be found within given forms. 
In the volume before us, with the title above given, we find a 
complete revision of both higher and lower groups, the synonymy 
carefully worked out, clear synopses given of the genera and 
species, with half-a-dozen well-executed plates and numerous 
woodcuts. It need scarcely be said that, embodying, as it does, 
the most recent views of classification and nomenclature, this 
volume will of necessity supersede all previous Catalogues of 
the Chelonians and Crocodiles which have emanated from the 
British Museum. 
A Catalogue of Canadian Birds; with Notes on the Distribution 
of the Species. By Monracue CuamBeruain. Sm. 4to, 
pp. 148. St. John, N.B. (McMillan, 98, Prince William 
Street). 
A Systematic Table of Canadian Birds. By Monracuz 
CHAMBERLAIN. Large 4to, pp. 14. St. John, N.B. (same 
publisher), 1888. 
AutTHouGH neither of these works can be accurately described 
as ‘“‘new books,” having lain for some months on our table, we 
have no doubt that they will be “new” to many of our readers, 
and some allowance may be made for the delay in noticing them 
on the ground of foreign publication, which generally implies 
delay in transit. 
Some authoritative work on the Birds of Canada has long 
been wanted, the very few volumes hitherto published on the 
