MR. A. H. GARROD ON THE MANATEE. 145 
able. My father, in 18511, described the teeth of the Tapir as presenting two pecu- 
liarities—the one, that the dentinal tubes of the crown of the tooth terminated beneath 
the enamel in oval dilatations, a most unusual manner of termination; the other, that 
vascular canals were to be found in the dentine of its roots. 
“The regular oval dilatations which terminate the coronal dentinal tubes of the 
Tapir’s tooth are as nothing compared to the great cavities into which the coronal 
tubes of the Manatee’s tooth would pass; and where there is one vascular canal in the 
dentine of the root of the Tapir’s tooth there are fifty in that of a Manatee. Yet it is 
remarkable that, besides an external similarity of form, the Manatee’s tooth should 
present what might be called an immense exaggeration of the two peculiarities which 
mark the dental tissues of the Tapir.” 
DESCRIPTION OF THE PLATES. 
PLATE XXVIII. 
Front view of the head of Manatus americanus, representing the extreme positions 
of the pads of the upper lip in the moyements described in the letterpress. 
Fig. 1. Lip-pads approximated. 
Fig. 2. Lip-pads separated. 
In both figures the nostrils are represented closed. 
PLATE XXIX. 
The liver of Manatus americanus. 
Fig. 1. Ventral aspect. 
Fig. 2. Dorsal aspect. 
PLATE XXX. 
The brain of Manatus americanus. 
Fig. 1. Lateral aspect. 
Fig. 2. Longitudinal section in the middle line. 
Fig. 3. Superior aspect, the upper part of the right hemisphere having been removed. 
Fig. 4. Inferior aspect. 
* Proc. Zool. Soc. 1851, p. 121. 
VOL. X.—Part 11. No. 2.— October 1st, 1877. x 
