DESCRIPTION OF PLATES. 
diameter of left tusk, 29 in. 
Width across the condyles, 7°6 in. 
transverse diameter of condyle, 2°5 in. 
post. diameter of occipital foramen, 
2°9 in. 
USE tal. 
penultimate, 4-4 1n.; width, 3-1 in. 
Length of two broken molars (surface), 11°7 in. 
Length of back molar, 7:4 in. ; 
Width of palate between anterior molars, 1°6in. 
51 
Vertical diameter of left tusk (approximate), 4° in. 
Antero-post. diameter of condyle, 3°5 in. ; 
Vertical height of condyle, 2°6 in. Antero- 
2-8 in. ; 
From anterior border of occipital foramen to niche of palate, 10°9 in. 
From niche of palate to beginning of diasteme, 12°7 in. 
above the body of the sphenoid, 5:5 or 6° in. 
transverse diameter of occipital foramen, 
Height of the pterygoids 
Width of outer surface of pterygoids, 
Length of anterior or 
width, 3:2 in. 
Width of palate, behind, 3°d in. 
PLATE XXXIX. 
Fig. 1.—Aastodon Perimensis. 
Lateral view of same skull as figured 
in Plate XXXVIII., described above.—B.M. 
Fig. 2.—Mastodon Perimensis. 
Fig. 3.—Mastodon Perimensis. 
head, three different views. 
Palate view of same skull.—B.M. 
Occipital view of same skull.—B.M. 
Figs. 4, 5, and 6.—Mastodon Sivalensis. 
Fragment of small black 
The specimen is very perfect in form, 
without crushing, so far as it goes. 
that of the frontal ina slightly rounded manner. 
The plane of the occiput meets 
The ligamentary 
depression is placed about the middle of the occiput, and is not deeply 
marked, consisting of a dividing crest, separating two diverging pits, 
having a heart- shaped outline. 
and from base to top. 
M. Perimensis. 
occiput) is inclined to be sharp. 
bosses as in Elephant. 
M. Ohioticus. 
“The occiput is slightly convex across 
The condyles do not project backwards as in 
The posterior boundary of the temple (edge of 
There is no tendency to occipital 
The occiput in some respects resembles that of 
There is a very obtuse convexity or boss on the middle 
of the forehead between the temples.—B.M. 
Greatest width of occiput (the half doubled) 22- in. 
surface of condyles, 17° in. 
Interval across the condyles, 7:1 in. 
Height of occiput from 
Contraction of brow between the t temporals, 11°8 in. 
Antero-post. diameter of left condyle, 4:1 in. 
Transverse diameter of left condyle, 2°5 in. 
Fig. 7.—Mastodon Sivalensis. 
a cast in B.M. 
Fragment of upper jaw with two 
. molars, broken end of incisives, and anterior portion of zygoma. 
From 
PuatTe XL. 
Figs. 1 and 1 a.—Mastodon latidens. 
with two ridges.—B.M. 
Second? upper milk molar 
Length, 1:9 in. ; width, 1-4 in.? 
Figs. 2 and 2a.—M. latidens. 
four ridges.—B.M. 
Third? upper milk molar with 
Length, 3°in.; width, 1°8 in. 
1 In the Museum of the Royal College 
of Surgeons is the left side of the upper 
jaw of a young Mastodon latidens con- 
taining the first and second milk molars. 
The anterior tooth is about 1-in. long 
and ‘8 in. wide, and has two ridges with 
a heel. The main ridge is transverse ; 
the anterior one is an obtuse cusp. 
The tooth is oval, the sharp end being | 
The second milk molar is 2° in 
It has three 
in front. 
long by about 1- 5 in. wide. 
main transverse ridges and a small 
bourrelet ridge in front, and a_ heel 
ridge behind. It expands very widely 
in the direction of the orbit. A vertical 
section shows something like the enamel 
of another small tooth, 3 “ineh long.—H.F. 
