698 GEOLOGICAL SURVEY OF THE TERRITORIES. 
back of the tarsus. At the present writing we know of no author who 
has very recently added anything to the literature of this subject, bear- 
ing upon this particular point, and the writer was quite confident that 
all he had said in his Grouse paper could be sustained; for if this process 
did not separately ossify in the Tetraonide, and thus weaken its claim 
as being a homolonge of one of the tarsal bones, why should this not 
be the case among all birds? A few months ago we made a discovery 
that again shook our faith in this 
matter, and led us to believe that 
perhaps this process was more 
entitled to the appellation of the 
calcaneal than we had previously 
S supposed. The facts in the case 
are these, and we must leave our 
reader to draw his own conclu- 
sions. We have before us the 
tarso-metatarsus taken from the 
\ young of two widely-separated 
genera and families. The first 
is that of the chick of Pediecetes, 
= one of our present genera; the 
= second is from the young of Cin- 
clus meaxicanus, the American 
gue ul) Water Ousel. In the first we 
aes observe all those characteristics 
Tophoriyx californica. that we have already ascribed to 
this family in general, and elucidated above; but in the tarsal joint of the 
Dipper, our second example, we find that the centrale and the so-called cal- 
caneal process are connately developed; the latter element being of good 
size already shows the grooves for the flexor tendons. Of the number of 
points of ossification in this development in Cinclus the author can say but 
little, as his material has been chosen from a few of these birds, furnished 
by the Smithsonian Institution. The subject is an extremely interesting 
and important one, and will well repay further investigation and research, 
and the author only regrets that at this date he can make but such 
slight additions to what we already know of it through the exertions and 
examinations of others. In any of our adult Grouse, this process is verti- 
cally grooved and perforated for the passage of tendons; fromits inner and 
posterior angle in many of the Tetraonide it sends down a thin plate 
of bone that usually meets the shaft at junction of upper and middle 
thirds, occasionally running further down to become confluent with it in 
every instance; this feature is rarely present in the Quails. In Centro- 
cercus and others the hinder aspect of the tarso-metatarsus is sharply 
marked by muscular ridges. The superior and articulating surface of 
this bone displays eminencies and depressions fashioned to accommodate 
themselves to the condyles of the tibia; a tuberosity on the anterior mar- 
gin in the articulated skeleton fits into the intercondyloid notch of the 
bone. Below this the shaft in front is scooped out, having at the base 
of the depression two small elliptical foramina, side by side, and to the 
inner side of its boundaries one or two pointed muscular tubercles. The 
distal ani! transversely expanded end of the bone presents the foramen 
for the anterior tibial artery, occupying its usual place, and the three 
trochlear apophyses for the toes, the middle one being the largest and on 
the lowest level. The two lateral ones, separated by wide notches from 
the former, are thrown but a limited distance to the rear, so that the 
concavity behind them is not peculiar for any great amount of depth. 
