236 REVIEWS. 
The present paper witnesses his laborious and conscientious appli- 
cation, rewarded with gratifying results in the elucidation of a 
difficult subject. Hitherto, we are bound to say, our Raptorial 
birds have been investigated with only moderate success, and, in 
fact, their technical details of form, etc., have never before been 
properly worked out, nor adequately presented. To this is due 
much of the prevalent and acknowledged confusion, for which, for- 
tunately, there will hereafter be little excuse. Mr. Ridgway’s 
analyses and diagnoses are drawn with care and precision, and 
carried to such circumstantial detail, that his paper is really 
the next best thing after specimens themselves. He shows a 
“hawk’s eye” for differences, and skill in rendering them antithet- 
ically ; if his generalizations keep pace with his analysis, he will 
not be in danger of losing the broad bearings of a subject in the 
very richness of detail that he elaborates. But a certain embar- 
rassment in this respect may be found, as a matter of typographi- 
cal execution; at least, we confess that we studied out the inter- 
relation of some of the numbered and lettered paragraphs with 
difficulty. Besides this small point, the omission, in treating of 
external characters, of. any reference to the ear-aperture of Circus, 
and mention, in several places, of the tibio-tarsal joint as the 
“knee,” call for criticism. 
The classification is based upon a character that has hitherto re- 
ceived little or no attention :—the condition of the os lachrymale, 
that, in most Faleconide, forms a projecting superciliary shield, 
or “eye-brow,” and mainly confers the decided and threatening © 
gaze of these birds. This, with the shape of the nostrils, the 
toothing or lobing of the tomia,* some points in the structure of 
the feet, and the facial disc of Circus, furnish a basis for six sub- 
families — Falconide, Circine, Accipitrine, Haliaetine, Milvine 
and Polyborine. If reliance, primarily, upon any single charac- 
ter seems always more or less arbitrary, it is often surprising how 
well it works, in marking off sections already determined upon 
other grounds. Thus the absence of a superciliary shield distin- 
guishes Milvine and Polyborine from all the rest. -To those of 
us, however, who always associate Pandion with Haliaetus, it is a 
novelty to find the genus placed in Milvine; although, as the sur- 
prise wears off, we may well ask why not, seeing how many char- 
acters Mr. Ridgway shows that it shares with Elanus, among them 
*Tomia (Gr. Towos, a Cutting, from yewve); “the cutti d f the mandibles.” 
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