662 
The An. 
Naturalist. 
myself/ that the Edentata are descended from mammalia with 
enamel-covered teeth. Such forms as the Taeniodonta of the 
North American Eocene correspond to such a type. These ani- 
mals were armed with the powerful fodient claws, and the texture 
of their bones was much like that of Edentata. The enamel is 
much reduced on the adjacent faces of the teeth. 
Ancestral forms of some of the families have been found in 
the upper Miocene (Loup Fork) beds of North America. The 
Caryoderma snoz'iannm Cope, from 
Kansas, was a Glyptodont with par- 
tially developed carapace, consisting of 
osseous nodules. (Plate XXXII.) The 
plates covering the tail were better 
ossified, apparently forming rings of 
acuminate tuberosities as in the genus 
Hoplophorus. Hoofs of a similar 
form, from Texas, are described by 
Leidy. The genus Glyptodon ex- 
extended its range to North America 
F:o. .. d"""S P"«™^ '''"'■'• '^ ^P-'- "■- 
abundant in the valley of Mexico at 
that period, and specimens of probably the same from south- 
western Texas and Florida have furnished the basis of our 
knowledge of the G. petalifcrus Cope. (Fig. 2.) Leidy has 
described a still larger species {G. floridamis) from the state 
after which it is named. 
The genera of the family may be defined as follows : 
I. Teeth with two internal and two external ribs. 
Last two molars prismatic ; grinding faces 
plane ; Nothropus Burm. 
Scuta of carapace nodular ; (? teeth)*^ Caryod^ 
Scuta of carapace quadrate ; Chlamydotlia 
