8o 
Sclater on the Sy sterna Avium. 
has caused Sundevall to place them at the end of his division 
Psilopaedes*) , and, no doubt, belong to a new line of departure 
from the Passeres towards the Gallinae. It is very hard to have 
to mar the symmetry of the Columbine group by adding to it the 
Pteroclidae. Yet there can be no doubt that in most respects the 
Sand-Grouse are more truly Pigeons than Grouse, and that the 
only way to escape from the dilemma is to recognize the Ptero- 
cletes as a separate order, as Prof. Huxley has proposed to do, I 
intermediate between the Columbae and Gallinae. 
As regards the divisions of the Columbae into families I have 
recognized two in the last edition of the 4 List of Animals ’ — 
Carpophagidae and Columbidae. To these should have been 
added a third (Gouridae) for the. Crown Pigeons, in which the 
tarsi have a very peculiar conformation, and perhaps a fourth 
(Didunculidae) for Didunculus. 
The Dodos must be held to belong to quite a separate section 
of the order. 
12. Galling, and. 13. Opisthocomi. 
As regards the true Gallinae, which we now come to, we can- 
not do better than adhere to Prof. Huxley’s excellent division of 
them into Peristoropodes and Alectoropodes. In the former sec- 
tion I have recognized two families, Cracidae and Megapodiidae ; 
in the latter two also, Tetraonidae - and Phasianidae. Whether 
the Meleagrinae and Numidinae should stand as subfamilies of the 
Tetraonidae (as arranged in the 4 List of Animals’ for 1879), or 
as separate families, is, I think, not quite certain. The Turnici- 
dae, there treated as only a family of the Gallinae, as also Opis- 
thocomus , must, I think, after Prof. Huxley’s elaborate discussion 
of the subject,]; be definitely constituted as separate orders, Hemi- 
podii and Opisthocomi — the former leading off towards the Cryp- 
turi, the latter most nearly allied to the Cracidae, and also showing 
manifest signs of alliance with the Coccyges among the Picariae. 
14. Geranomorphje. 
In the 4 Nomenclator ’ I have placed the Rails next after the 
Gallinae, to which they show manifest symptoms of relationship, 
* Tentamen p. 97. 
+ P. Z. S. 1868, p. 311. 
f P. Z. S. 1868, p. 254. 
