PROFESSOR FLOWER ON THE RECENT ZIPHIOID WHALES. 223 
that in life the tooth was entirely concealed’. The height of the right tooth from 
the middle of the base to the apex is 1°8 inch, the length of the base is 1:1 inch, 
the length of the anterior margin is 1°5 inch, of the posterior margin 2 inches, the 
greatest thickness 0°6 inch. The left tooth is slightly larger than the right. 
A longitudinal section in the antero-posterior direction having been made through 
these teeth, their structure was seen to be very similar to that of Mesoplodon sowerbyi, 
as described by Mr. E. Ray Lankester’. In the larger anterior tooth the only remains 
of the pulp-cavity is a small irregular vacuity (p), an inch below the apex of the tooth, 
and consequently more than an inch and a half from the base. The true dentine (d) is 
limited to the portion of the tooth above this spot, the large bulk of the tooth below 
being composed of very coarse-looking osteo-dentine with numerous wavy fissures and 
channels, having a general longitudinal direction ; immediately around the pulp-cavity 
a tissue (vy) having a botryoidal or globular arrangement forms a transition from the last- 
named structure to the true dentine. There is no enamel. ‘The surface of the tooth, 
except at the apex and base, is covered with a layer of cement (c), which nowhere 
exceeds ;'5 inch in thickness. The constituent elements of the smaller tooth are 
arranged in a precisely similar manner. 
Hyoid bones.—The basihyal and the thyro-hyals are not yet united (Pl. XXVIII. 
fig.9). The former is more elongated transversely than in Hyperoodon, being 5:8 inches 
in width, and 2-7 inches in antero-posterior length at the middle. The posterior 
border is straight; the anterior border excavated in the middle, and with a roughened 
prominence near each end for the attachment of the anterior cornua. 
The thyro-hyals are each 9 inches long, and 2°5 inches in greatest diameter. Their 
under surface is flattened. They are less wide in proportion to their length than in 
Hyperoodon, and thus, as in so many other details of the skeleton, they show that Berar- 
dius recedes further from Physeter than does that genus*, and consequently approaches 
nearer to the ordinary Dolphins. 
The stylo-hyals are 14 inches long, and 2-9 inches in greatest thickness, slightly 
curved, and with three distinct surfaces bounded by three longitudinal ridges, the 
broadest and flattest surface being in the concave side of the bone. Towards what 
appears to be the upper end there is a neck-like constriction, surmounted by an 
expanded and obliquely truncated head. 
Vertebral Column.—The numbers of the vertebre are:—cervical 7, thoracic 10, 
’ See the remarkable observations upon the teeth of the animal when alive, recorded by Dr. Haast (p. 214), 
and the mention of “ muscular bundles” by which they are moved by Dr. Hector (p. 216), which accord so 
little with any thing hitherto known in mammalian anatomy, that further observations on this subject are 
extremely desirable. 
? Transactions of the Royal Microscopical Society, new series, vol. xv. 1867, p. 55, 
* The breadth and flatness of the thyro-hyals is eminently characteristic of both the genera of Physeterine, 
Physeter and Kogia; and the affinity of the Ziphiinz to them is in this respect only slightly marked, though 
most so in Hyperoodon. 
