604 The American Naturalist. [July, 
incisors are far too large to be associated with the premolars of 
H. sculptus and H. serratus, we have further grounds for asso- 
ciating them with Meniscoéssus, with which they agree in size. 
The tooth (Fig. 7) assigned by the author as the upper incisor 
of Dipriodon robustus apparently belongs to a reptile. It is 
unlike any incisor hitherto found with the Multituberculata. 
Plagiaulacide. Dipriodontidæ. 
ș7-7-------4=-4 Dipriodon lunatus. 
Caw Dipriodon robustus. 
Halodon sculptus ...-. 



Tripriodon caperatus ,,.-\\ 
4 Roo FON AN “\---. Tripriodon celatus. 
Tripriodontidee. 
re ae wat Selenacodon fragilis. 
. Trip i i i 
FIG. 8.—Upper and lower molars of Meniscoëssus in position. (Association of incisors 
with molars conjectural.) 
The accompanying restoration is based upon the foregoing 
considerations, and show that, according to the author, the relation- 
ships of Meniscoëssus are as varied as those of its contemporary, 
Cimolomys, including three families, four genera, and seven species., 

FIG. 8a.—Ctenacodon pen Marsh, 4 inner view of right upper jaw; 4, ventral 
view of same; a-d, first to o fourth premolar, as interpreted by! Marsh. After Marsh. 
14. Allacodon lentus and A, Siesta (Pl. vu, Figs. 22-26-31). 
The types are described as upper molars of a genus related to 
Allodon and Bolodon, and referred to the 
Allodontide.—It is a universal characteristic 
of the molars of the Multituberculata that, as 
oo ee the grooves are adapted for fore and aft wear, 
Tenms. “Ader Man Me tubercles are arranged on the sides. In 
= the type of Allacodon a tubercle stops the 
= a : these me are | = adaptec pes and aft To aa are, 




