18 ! Storer on the 
Natural History ; it is compactly armed with long 
firm very sharp spines. 
Anterior extremities, thirty-five inches long, round- 
ed at the origin, compressed in the middle, taper- 
ing to a rounded EE in their widest por- 
tion, ten inches across. 
Posterior extremities, sixteen pie ue in length ; 
for about half their length, nine inches wide, trun- 
cated posteriorly, and, as well as the anterior ex- 
tremities, bordered upon their posterior margin by 
a deep fleshy fringe or border. 
Length of the tail, thirteen inches ; eight inches 
wide at the base, tapering to a point. 
Body beneath, covered by a less firm envelope, of 
a lighter color. 
I am indebted to my friend Dr. Wyman for the 
accompanying plate of this species. 
