744 PTARMIGAN—PTERYVLOSIS 
PTARMIGAN, Gael. Tarmachan, see GROUSE (p. 392, note). 
PTEROCLETES,! Mr. Sclater’s name (bis, 1880, p. 407) for 
the Order composed of the SAND-GROUSE, equivalent to the 
PTEROCLOMORPH of Prof. Huxley (Proc. Zool. Soc. 1868, 
p- 303), which itself was anticipated as a group by Bonaparte’s 
Pediophili in 1831 (Saggio &e. p. 54). 
PTERYGOIDS, a pair of bones in the roof of the mouth of every 
bird, articulating with the QUADRATES and the anterior end of the 
PALATALS, as well as, directly or indirectly, with the Basi-sphenoid 
and other parts of the SKULL. ; 
PTERYLOSIS signifies plumage considered in regard to the 
distribution of its 
growth. In only a 
few Birds do the 
FEATHERS grow over 
the whole body, but 
they are generally 
restricted to  well- 
defined patches or 
tracts, which in 1833 
received from Nitzsch 
(Pterylographix Avium 
pars prior, p. 11) the 
name of preryla(arepoy, 
pluma ; brn, sylva) or 
“‘feather-forests,” in 
opposition to the ap- 
teria, or featherless 
spaces, which inter- 
vene. Presumably 
the first bird-like crea- 
tures had their skin 
uniformly — clothed ; 
but the /tatite, Sphen- 
asct and Palamedea are 
almost the only exist- 
ing forms having the 
‘ Contour - feathers ” 
Boravrus steLiaris. Ventral and dorsal aspect. (p. D4 1) evenly dis- 
The dark patches shew the ‘‘ Powder-downs.” 
(After Nitzsch.) 
posed over the body. 
It would be, however, 
' Tt is no more easy to find a plural for the word Prerocles than for Patrocles, 
Themistocles or many others, but we may be quite sure that it would not take 
this form. Sundevall many years ago (A. Vet.-de Handl. 1836, p- 119) had 
Fteroclides, which is perhaps possible. 
