OTHE MOLAR SEEIES OP RHINOCEROS TICHORHINUS. 537 
stout than the rest of the fangs, the consequent depth and size of the 
alveolus has given rise to the supposition, that it must have be¬ 
longed to a premolar one. In one specimen, in my possession, it is 
visible even after the appearance of Pm 2 above the jaw. 
A beautiful figure of this tooth is given in the British Foss. Mam. 
fig. 137, together with a description, page 339. The vertical 
height of an unworn crown from Wookey Hole is 0*6 inches. 
Measurements: 
(l) (2) (3) (4) 
Wookey Hole . . . 06 . 04 . 0.46 . 20 
Wookey Hole .... 0*5 . 0 - 38 . 045 
Lawford .058 . 036 . 0545 
2. Dm 2. (Fig. 5, 6, /3) In Dm 2, the median groove is strongly 
impressed, the depression dividing the first from the second costa 
is shallow and wide. The second costa (K 2) is by far the most 
prominent. The anterior valley (A) is well marked, open, and sub¬ 
divided into three portions by two small processes of enamel, of 
which the middle is the larger. The deep posterior valley (B) is 
constricted by the posterior extension of the median collis (E). This 
bears a faint cusp posteriorly about | of the length of tooth from the 
base of crown. 
Measurements: 
(1) (2) (3) (4) 
Lawford ..... 085 . 05 . 06 
Wookey Hole .... 0*95 . 0‘53 ; 065 . 2'8 
Wookey Hole .... 0 85 . 0'53 . 06 
3. Dm 3 - 4. The following characteristics, which obtain in a large 
number of teeth, show that they are either the third or the fourth 
milk molars. I can detect no difference between them. The median 
groove (I) is well developed, and insulates the anterior from the pos¬ 
terior lobe, as in the true molars. The anterior area (M), the higher 
of the two, is flattened, and divided into two costae by a vertical de¬ 
pression, more or less deep. The anterior valley (A) is at a higher 
level, and smaller than the posterior. The anterior collis (D) is larger 
than the posterior, and is flattened. 
The tooth y in Figs. 5 and 6 is the third of the milk series. 
Measurements : 
Dm 3 
(i) 
(2) 
3) 
Jaw, Wookey Hole 
1-35 
. 0*75 
. 076 
„ Lawford . . . 
1-33 . 
, 0-73 . 
, 075 
„ Thame .... 
1*3 . 
, 083 . 
, 083 
Dm 4 
Jaw, Lawford . . » 
1-3 
. 08 
. 0-88 
„ Thame .... 
1-36 
. 093 
. 925 
