Cricetus songarus.
Upper jaw —
Length. Width.
Diastema 0.30
Molar series 0.19
PM 4 0.07 0.05
M l 0.05+ 0.05-
M 2 0.04- 0.04
Lower jaw.
Diastema 0.18
Molar series 0.17
PM 4 0.07 0.05-
M 1 0.06 0.05-
M 2 00.5 0.04-
EXPLANATION OF PLATE.
Plate VIII.
Fig. 1. Arvicola ratticeps. Upper jaw, lateral aspect.
1 a. Dentition of the upper jaw, magnified six diameters.
1 b. Lower jaw, external aspect.
1 c. The same, internal aspect.
1 d. Dentition of the lower jaw, magnified six diameters.
2. Arvicola Guliemi, n. s., lower jaw, external aspect.
2 a. The same, internal aspect.
2 b. Dentition of the same, magnified six diameters.
3. Lemmus norvegicus (var.), lower jaw, external aspect.
3 a. The same, internal aspect.
3 b. Dentition of the same, magnified six diameters.
4. Lemmus torquatus (var.), anterior part of the skull, lateral aspect.
4 a. Dentition of the same, magnified six diameters.
5. Lepus diluvianus, skull, natural size, lateral aspect.
6. Cricetus songarus, anterior portion of skull, lateral aspect.
6 a. Dentition of the above, magnified six diameters.
6 b. Lower jaw, external aspect.
6 c. The same, internal aspect.
6 d. Dentition of the lower jaw, magnified six diameters.
k2
