92 
Few York, forwarded liis large and remarkably fine collection for study 
in this connection. Altogether, we have been enabled to examine and 
compare upward of four hundred specimens, including thirteen species, 
as follows :— 
List of species and specimens examined. 
1. Xisus cooperi. 
2. Xisus gundlaclii. 
3. Xisus bicolor. 
4. Xisus pileatus. 
5. Xisus chilensis. 
6. Xisus chionogaster... 
7. Xisus salvini. 
8. Xisus ventralis. 
9. Xisus uigroplumbeus. 
10. Xisus erythrocneruis. 
11. Xisus fuscus_ 
12. Xisus tinus. 
13. Xisus collaris. 
Total. 
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Mus. O. Salvin. 
Mus. Vassar College. 
Mus. S. F. Baird. 
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Of the above-named species, three are not included by Mr. Sharpe : 
A. gundlaclii , being mentioned in a foot-note, and doubtfully referred 
to A. cooperi; N. uigroplumbeus , is referred to N. ventralis , while JST. salvini 
is new, and first named here. On the other hand, there are two species 
of this genus which we have not seen, viz, N. guttatus and N.fringil- 
loides , both of which appear to be perfectly distinct. 
Subgenera. 
• 
Kegarding subgeneric divisions of the above group of species, sev¬ 
eral have been proposed and named, but we are unable to make out more 
than two which are capable of definition ; these two groups constitute 
quite distinct subgenera, and may be characterized as follows :— 
Aisus.—Five outer primaries, with inner webs emarginated; fourth 
or fifth quills longest$ inner toe not reaching middle of second joint of 
middle toe. 
Hieraspizias.— Four outer primaries, with inner webs emarginated ; 
hird or fourth quills longest; inner toe reaching to or beyond middle 
f second joint of middle toe. 
Subgenus NISUS, Cuvier. 
Accipiter Brisson, Orn. i, 17G0, 10.—Type, Faico visits Linn. (— X. fnngillarius). 
Xisus Cuvier, Legons Anat. Comp, i, tabl. ois. 1799.—Same type. 
Ierax Leach, Syst. Cat. Mam. etc. Brit. Mus. 181G, 10.—Same type. 
Cooperastur Bonaparte, Rev. et Mag. de Zool. 1854, 538.—Type, Faico stanieyi Aud. 
(= X. cooperi). 
Leptohierax Sundevall, Disp. Acc. Hemeroharp, 1872, 24— Same type. 
Characters. —Five outer primaries with inner webs emarginated ; 
fourth or fifth quills longest; inner toe reaching scarcely beyond the 
first joint of the middle toe, or falling short of it. 
