62 Ray Lankester, on the Tooth in Ziphius Sowerbi&nsis. 
absence of any sections, certainty is impossible, there can, I 
think, be little doubt that the structure of the tooth of 
Layard’s Ziphius agrees with that of Sowerby’s, and assuredly 
the small projecting caps of dentine are identical. Some 
zoologists are inclined to regard the strange overlapping 
teeth of j Dolichodon Layardi as deformities. Dr. Gray, how- 
ever, does not incline to this opinion. The two teeth are 
almost exactly alike, and very regular and definite in form, 
and certainly have not the aspect of abnormal growths. 
Whether deformities or not, their function is in the highest 
degree obscure ; and, supposing that they have grown to an 
abnormal size, their essential composition and form is pro- 
bably unaltered. 
Berardius. The figures given of the teeth of the tetrodont 
Ziphioid Berardius by Duvernoy appear to indicate a nipple- 
shaped termination to a broad flattened tooth— as in Micro - 
pteron* 
A second male specimen of Sowerby’s Micropteron has 
recently been cast ashore in Ireland, and the skull is pre- 
served. It is desirable that the teeth of these specimens 
should be examined, as also those of the other ziphioids in 
various museums, both by simple and microscopic sections. 
Fossil ziphioid teeth from the Red Crag. The woodcut, 
fig. 1, represents a remarkable compressed claw-like body 
Reduced to one half the natural size. 
from the Red Crag ; three other specimens similar to it are in 
* Since this paper was read I have seen the first part of a paper by M. 
Fischer in the ‘ Nouvelles Archives du Museum/ 1867/ 3rd vol., “ Oil the 
Cetaceans of the genus Ziphius” He does not appear to have examined 
the structure of the tooth in any of the species he quotes, but I hope may 
be induced now to ascertain if the structure here described is common to 
the Ziphioids in his charge. 
F/G-' 2. 
