634 GEOLOGICAL SURVEY OF THE TERRITORIES. 
are also present, but a lens of some power is required to study their 
form and arrangement. 
The hyoid arch—(P1. IV, Fig. 37, seen from below).—This, the hemal 
arch of the parietal vertebra, in no way deviates in this little Lark from 
the usual ornithic characters possessed by it among living birds, in being 
freely suspended beneath the cranium and acted upon by certain mus- 
cles. The glosso- and cerato-hyals seem to be confluent, and the bone 
thus formed consists in two narrow little affairs, that for their. anterior 
two-thirds run alongside of each other with a greater or less intimacy, 
to have their tips slightly diverge anteriorly. Posteriorly the ends have 
a still greater amount of divergence, and at the junction of the middle 
and posterior thirds there is a transverse bony bridge, that bears the 
facette for articulation with the basi-hyal behind. Scarcely any antero- 
posterior curvature exists. The posterior tips overhang the articula- 
tion of the thyro-hyals with the confluent basi- and ‘uro-hyal. As we 
have never examined the tongue of the young of Hremophila, we may 
be in error in saying that the glosso- and cerato-hyals are confluent, as 
the bones we have just described may be the cerato-hyals alone, the 
glosso-hyal being entirely in cartilage. The posterior tips of the cerato- 
hyals have an expansion to accommodate the articulation referred to, 
bearing on either side small, elliptical, articular surfaces, looking back- 
wards and outwards for the heads of the hypo-branchial elements of 
the thyro-hyals. 
The bone is subecompressed from above downwards, the uro-hyal being 
produced behind by cartilage, or rather tipped by that material, while 
the articulation at the anterior extremity of these confluent bones is 
hidden from view in the superior aspect of the arch by the glosso- and 
cerato-hyals; and, as is common, the inferior lip that the basi-hyal lends 
to this joint is the longer, and protrudes forward. 
The hypo- and cerato-branchial elements of the thyro-hyals are very 
long, slender, up-curved little bones, produced posteriorly, as is the uro- 
hyal, by cartilaginous tips. 
The shaftlets of these delicate elements are slightly flattened from 
above downwards, as are their articular heads. The free extremities 
have a tendency to curve inwards a little, or towards the median plane, 
as well as upwards. 
The lower mandible—(Plate IV, Figs. 22 and 29).—Hremophila_ is an- 
other example exhibiting the non-approximation of the tomial edges of 
the mandibles in the dry skull, this feature being more often absent 
among Grallatores and many of the Natatores, where these edges come 
in contact with almost an equal amount of exactness as where the bill 
is armed with its horny theca. 
The lower mandible of the Horned Lark seems to be, in point of struct- 
ure, composed almost entirely of compact tissue, and, owing in addition 
to the thorough coalescence of its primary elements, a very firm and 
strong bone. Sutural traces, the indicators of the boundaries of pris- 
tine segments, have entirely disappeared, and no one would ever suspect, 
in examining it, the presence of nine original parts, were he not familiar 
with avian osteology or had the opportunity of dissecting the young. 
The inferior surfaces of the articular ends are ona level with the major 
part of the under rim of the rami, but they are well below the coronoidal 
elevations on either side. They present superiorly the usual undulatory 
surface to meet and articulate with the condyles of the tympanics. 
_ Below appears a longitudinal ridge, due to the extension upon that side 
of the ramal edges. A knob-like process projects behind, and the true 
articular processes are sharp and rather long. They are directed in- 
