22 Mr. E. D. Cope on the Bunotherian Mammalia. 
of them (Jfythomys, Solenodon, Chrysochloris) have but 
weakly developed canine teeth, and Chrysochloris has large 
incisors. As an extreme form Hsthonyx will follow, standing 
next the Tillodonta. It will then be necessary to transfer 
the Arctocyonide and all the Mesodonta to the Insectivora, 
where they will find affinity with the Tupzide. These have 
well-developed canines and small incisors, as in the extinet 
groups named. ‘The Chiromyide must be distinguished from 
all the other suborders, on account of its rodent-like incisors 
combined with its lemur-like feet. 
The characters of the six suborders will then be as fol- 
lows :— 
I. Incisor teeth growing from persistent pulps. 
Canines also growing from less persistent pulps, 
agreeing with external incisors in haying mo- . 
lariform crowns ...... Set Oe s Oats eee er 1. Teniodonta. 
Canines rudimental or wanting; hallux not 
opposable...... oF caldera ites eons op ee aeTic Jo Ne 11. Tillodonta. 
Canines none; hallux opposable ............ 1. Daubentonioidea. 
Il. Incisor teeth not growing from persistent 
pulps. 
Superior true molars quadrituberculate ; hallux 
GPPOSADIE ® hieio es 5 Sracuis: era catsiots ee ene eee Iv. Prosimie. 
Superior true molars quadrituberculate ; hallux 
BIO LAG PPOSHDIO oS ccrs ore csesste eye Siererele mis eas reve v. Insectivora. 
Superior true molars trituberculate or bituber- 
culate *; hallux not opposable ............ vi. Creodonta. 
While the above scheme defines the groups exactly and, 
so far as can now be ascertained, naturally, I do not doubt 
that future research among the extinct forms will add much 
necessary information which we do not now possess. It 
is possible that the group I called Mesodonta may yet be 
distinguished from the Insectivora by characters yet unknown. 
But I cannot admit any affinity between this group and any 
form of “ Pachyderms,” as suggested by Filhol, or of Suil- 
lines, as believed by Lydekker ft. Such suppositions are in 
direct opposition to what we know of the phylogeny of the 
Mammalia. These views are apparently suggested by the 
Bunodont type of teeth found in various Mesodonta; but that 
* The internal tubercle is wanting in the last two superior molars in 
Hyenodon. ‘This genus, of which the osteology remains largely unknown 
has been stated by Gervais to possess a brain of higher type than the 
Creodonta, Prof. Scott, of Princeton, however, is of the opinion that 
this determination is erroneous, and that Hy@nodon is a true Creodont 
in this and other respects. If so, the genus will perhaps enter the 
Amblyctonide. 
+ Memoirs Geological Survey of India, ser. x. 1883, p. 145. 
