84 MEMOIRS OF THE CARNEGIE MUSEUM 
Antero-posterior diameter of P; at the base of crown ‘race SS 
Transverse 6 Ce Pie “ « a1 
Antero-posterior  ‘ “Pp, “ te 
Transverse Gu Ge eee edt te « 
Antero-posterior — ‘‘ “py, « ce “ 
Transverse “ “op, “ “c 
Antero-posterior CL rf oe te “ 
Transverse “ fpr “ 
Antero-posterior — ‘‘ tM, * “ “ 
Transverse “ oMe te « 
Antero-posterior  ‘‘ ber ena “ 
Transverse Ob i Le ce cs 
Antero-posterior ‘‘ Cenc! “ “ 
Transverse oe MV ieee? “ “ 
Tue Minx Denrrrion. 
(Plate LIX.) 
In section 12, block 66 (see Plan of Quarry, Pl. LIV), were found the remains 
(No. 2137, Carn. Mus. Cat. Vert. Foss.) of the skull, and close by in another block, 
a portion of the lower jaw of a young individual, with the dentition partly in 
place. An incisor is represented only by the crown ; the tooth being too young for 
the formation of a fang. This incisor is pressed by the matrix close to the canine 
and has a simple conical crown slightly crinkled at the base and it is very thinly 
covered by enamel. The only noticeable difference between this tooth and more 
adult forms of the canine is its strongly serrated anterior and posterior ridges and 
the crinkled enamel. By excavating the alveolar border at the antero-internal 
angle of the deciduous canine the crown of the permanent canine was found. 
The point of the crown of the permanent P+ appears in the circular alveolus 
immediately back of the canine. It is thus seen that the temporary P* had a single 
fang and was crowded out quite early. Professor Scott has also (87, p. 276) pointed 
out a similar occurrence observed by. him in a young specimen ot Archxotheriwm 
which would tend to firmly establish the fact that there are four deciduous premolars 
in the upper jaw of at least two genera of this family. Deciduous P of the specimen 
under description is represented only by the alveolus, while the deciduous P* is in 
position in the right maxillary and P+ again represented by alveoli. In the left 
jaw temporary P* has been placed in position. Deciduous P24 of this specimen has 
two large cusps and two smaller tubercles. The anterior cusp (protocone) is a 
bluntly pointed pyramid which occupies the anterior half of the crown, while the 
postero-internal cusp (tetartocone) is smaller, and is confined to about one quarter 
