674 GEOLOGICAL SURVEY OF THE TERRITORIES. 
serves the purpose of keeping this free ossicle in its socket in certain 
movements of the jaw. 
Peculiarities of the floor of this cavity have already been described 
above; in specimens of Canace canadensis, carefully selected for me by 
Mr. William Brewster, of Cambridge, Mass., and forwarded to me by 
Prof. J. A. Allen, of the Museum of Comparative Zoology, also of Cam- 
bridge, to whom my grateful acknowledgments are due for so many like 
favors, we find, upon viewing the skull from below, the elevations or 
convexities due to these ellipsoidal and wing-like formations, reminding 
one of their marked resemblance to the acoustic bull of the tympanic 
found among the crania of Felidae. 
The author in his various plates and figures believes he has given suf- 
ficient life size, as they all are, views of basal and superior aspects of 
the skulls of these birds, will not enter here into any needless details 
of measurements. The variation in size in this respect in Centrocercus 
has already been dwelt upon; itis not nearly so marked in other genera. 
The surfaces of the skulls above have a rough look caused by many 
minute depressions and groovelets, these running out to the margins of 
the orbits cause them in some to be finely serrated. 
The sharp-tailed Grouse is a unique exception to this, it being a bird 
of rather a delicate skull with smooth cranial superficies. All save Cen- 
trocercus possess rather depressed foreheads, apparently due more to a 
slight tilting upwards of the superior orbital peripheries. The lateral 
temporal fossz are shallow and scarcely noticeable, the muscles they 
afford lodgment not being remarkable either for their size or strength. 
Did the writer feel that he had sufficient material before him he would 
gladly devote a few of these pages to the description of some of the 
exceedingly interesting osteological differences existing between the 
domestic and the wild Turkey; but as such facts can only be considered 
reliable, and such differences constant, after the examination of a large 
series of each, such as we have not at present at our hand, we will 
simply speak of a few of the cranial peculiarities as seen in a set of 
skulls of Meleagris gallopavo and M. gallopavo americana from the col- 
lection of the Army Medical Museum of Washington. As we might 
expect, the skull of Meleagris has in it all of the leading points that we 
have attributed to the Tetraonide generally. The occiput and the for- 
amen magnum are found to be nearly or quite in the vertical plane, the 
skull resting on its bearing points in the horizontal plane; the surface 
above is more or less rough and venated, as in Cupidonia. The parietals 
rise above the general surface as rounded domes, constituting quite a 
prominent feature in the skull of this bird. A depression occurs in 
the frontal region between the margins of the orbit and posterior to the 
nasals; this is more decided in my specimens of Pavo cristatus, a bird 
that possesses a cranium not at all unlike the Turkey. In Meleagris 
we find the lacrymals to be strong and pointed bones directed back- 
wards, articulating principally with the nasals, though the frontals 
usually extend down to meet their posterior borders; below, their de- 
scending processes are flattened and turned towards the median plane. 
Taken as a whole the lacrymals of the Wild Turkey are quite different 
bones as compared with the same bones as we found them in the Grouse 
and Quails. A very interesting change is seen to take place in these 
bones in Vumida meleagris, as this bird attains maturity. We have just 
said that the frontals in the Turkey extended down so as to meet and 
articulate with the posterior borders of these bones on either side; now, 
the older the bird the more extensive is the meeting of these bones; 
this is carried to its maximum condition in Nwmida, for in the young of 
