ME. A. H. GARROD ON THE MANATEE. . 145 



able. My father, in 1851 \ 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 movements 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. 



' Proo. Zool. Soc. 1851, p. 121. 



VOL. X. — PART III. No. 2. — October 1st, 1877. 



