Recently Found Casioroides in Indiana. — Moore. 71 
In Castoroides the plates are nowhere so joined but that by 
the weathering of the cement they may fall entirely apart. 
There is no semblance of fangs to these grinders, but each 
tooth is set as a simple tenon in a mortise. 
I have no means at present of making a general comparison 
but I know of no other rodent with upper incisors so nearly 
surrounded with enamel. Instead of simply a plain enamel 
plate in front, as in the beaver and many other species of this 
order, we here have the grooved, striated and cross-wrinkled 
enamel, not only in front but over the outer, and part of the 
back surfaces. From this structure the crowns, instead of 
being beveled like a chisel tend to wear irregularly cup 
shaped with the proximal border lowest. 
The third cervical vertebra is so completely fused to the 
axis as to have no neural spine of its own. So close and so 
unsuspected was the union that the fact was for some time 
overlooked. Is it an exceptional case, or is it a mark of the 
species? It does not appear like an ordinary instance of an- 
kylosis such as we occasionally see in the dorsal or lumbar 
vertebrae of old horses, but to have more of the connate 
character of the cervical vertebra; in most cetaceans. 
The hind feet are very large, and from the divergence of 
the metatarsals and their well-rounded distal extremities, the 
long toes admitted of a great spread and were almost certainly 
webbed. The forelegs are not only so constructed as to admit 
of being very closely flexed at the elbow joint, but afford evi- 
dence that they were much of the time in that position. 
VI. A few Measurements. 
The entire length of the spinal column, as restored, includ- 
ing the head, is six feet two and a half inches. The length 
with the curves, as it stands mounted is five feet four inches. 
Length of head eleven and a half inches. The tail is two feet, 
nine inches, which is three inches longer than the cervical, 
dorsal. Lumbar and sacral series taken together. The hind 
foot measures eleven and a quarter inches. Entire length of 
upper incisors, following the anterior curve, is nine and one- 
half inches and their projection from the sockets, in front, 
is full :U inches. The lower incisors are 10| inches long and 
project 5 { i n<dies. 
