BALANODON PHYSALOIDES. 539 
Fig, 229. 
Microscopic structure of cement ; magnified 500 diameters. Balenodon. 
cular or medullary canals, few in number, and irregular 
as compared with those in the thick cement of the Mega- 
therium’s tooth, and more like those in the cement of the 
Physeter.* 
I have recently received from Professor Henslow the 
conical termination of the crown of two teeth of Balenodon, 
also from the Red Crag at Felixstow, showing the same 
ferruginous tint, brittle texture, and water-worn surface ; 
but retaining a shape more plainly bespeaking their dental 
nature. The diameter of the fractured base of the larger 
conical fragment is two inches; that of the obtuse apex 
about two-thirds of an inch: the length of the fragment 
being four inches; the tooth tapers more gradually 
to its summit, and is less curved than in the Cachalot. 
This fragment has belonged to part of a larger tooth than 
the one (fig. 226,) first determined, and the diameter of 
* I must refer the Reader to my ‘ Odontography,” p. 356, pl. Ixxxix, a, for 
an account of the microscopic structure of the Cachalot’s tooth, which may be 
compared with the account here given of the tooth of Balenodon, 
