4 
DESCRIPTIONS OF INFERIOR MAXILLARY BONES 
Anterior to this tooth are three alveolar depressions (Plate XX., 
m, n , o ) which mark the place of teeth which have been lost. 
Beneath the anterior socket is a foramen for the passage of blood¬ 
vessels and nerve. (Plate XX., fig. r.) At the anterior portion of the 
chin are two foramina for the same purpose: that on the left side is 
lower and larger than the other, pyramidal, and at a short distance bi¬ 
furcates. A fine needle may be passed some distance into each of these 
divisions. 
In one of the lower jaws of an adolescent Mastodon in the Finnel 
collection at New York, the foramen in the chin is two lines in diame¬ 
ter and passes directly into the large foramen in the ramus of the jaw 
occupied by the maxillary nerve and blood-vessels. 
The next specimen to be noticed, is a fragment of the right side of 
the inferior maxillary bone of an adolescent gigantic Mastodon , (Plate 
XXL) belonging to the splendid Wistar Museum of the University of 
Pennsylvania. This fragment is two feet five inches long. The 
general form of this jaw is similar to that of the gigantic Mastodon 
represented in Plate XXIII., but the ramus is rather more cylindrical, 
in which respect it resembles the specimen just described (Plate XX.). 
The upper portion of the coronoid, and the condyloid processes are de¬ 
ficient, as also the angle. The chin is also broken, but there are 
manifest indications of an expansion similar to that represented in 
Plate XXIII., s. Just above the base of the ramus internally are a 
number of circular depressions, probably formed by the lobules of 
the inferior maxillary gland. 
This fragment contains two teeth, and anterior to these a portion of 
the alveolus of a third tooth. The anterior tooth (Plate XXI. e) has 
three denticules, with two points each: it is five inches and eight- 
tenths long, and three inches and seven-tenths broad. The posterior 
tooth (Plate XXL/) has five denticules or pairs of points, and a trifid 
heel. This tooth is eight inches and one-tenth long, and four inches 
and three-tenths broad. 
The cabinet of the Society does not contain any specimen of the lower 
jaw presenting all the characters of the Mastodon giganteum , except 
a small fragment represented in Plate XXII. This fragment is twelve 
