
600 The American Naturalst. 3 [July 
A premolar (Pl. vi., Figs. 13-16) is rightly described as an 
upper premolar, and correctly associated with this genus (compare 
Fig. 19, Lemoine ” 
4. Cimolodon ities (Pl. 11., Figs. 5-8). wi 
The type is described as an upper molar 
representing a new genus and family, the 
Ns ae ee it with the EN T) EX 
lower molars of Ptilodus" Cope, it is SG, ch Neoplaginalax’ Le 
evident that the type is a first lower otk os remolan, 3-1. 
molar of one of the Plagiaulacide. 
5. Nanomys minutus (Pl. 11., Figs. 9—12). The type is described 
as a last upper molar of the left side, and referred to the Cimolo- 
dontidæ.—A comparison with Ptilodus shows that it is a last lower 
molar of the right side, belonging to one of the Plagiaulacidz.” 
6. Halodon sculptus (Pl. 111., Figs. 11-13). T)®typeis a fourth 
lower premolar, rightly referred to one of the Plagiaulacidz. 
A superior incisor (Pl. 111., Figs. 1-3) 
% is referred to this species. It ni 
A belongs to a much larger form. 
J o 7. Halodon serratus (Pl. 11., Figs. 14- 
a 7). The type is a fourth lower pre- 
molar, a smaller species rightly referred 
to one of the Plagiaulacidæ. 
—Halodon. Fourth í ae . 
inferiog “premolars sof ay H. A superior incisor (Pl. 111., Figs. 14- 
ormosus. . After Pe aji 17) is referred to this species. It ap: 
parently belongs to a larger form. 
tisa etic fact that the upper molars of the Plagiaula- 
cide have three rows of tubercles, while the lower molars have 
but two, and that the cusps of the lower rows fit into the valleys 
of the upper teeth. This is beautifully demonstrated in the 
author’s own figures as here reproduced and rearranged in Figure 
3: ais the type of Cimolomys gracilis, which fits upon c, the type 
of Cimolodon nitidus; while b, the type of Nanomys minutus, 
COT i acs S 
Pek 


10 Op. cit., Pl. vI., Fig. 19e. 
il This type iC. nitidus) has s four internal ane seven external tubercles; while Pzilodus 

n “The Tertiary MN Coe AM. Nat. „Jas, 1884, P- 694- 

