a ee 
Oe Beall —r — 
ON THE MANATEE. 305 
this, no doubt, led Vrolik* to regard ‘the structure of the upper lip 
as plainly an erectile tissue.’ ’’ Observations on the living animal 
verify the correctness of Vrolik’s surmise. It is a post mortem change 
which causes the thickly bristled erectile lip-pads to be directed 
downwards. In the living animal their erectile fissue is distended 
with blood on most occasions, especially whilst feeding, and the pads 
are by this means directed inwards, towards one another, in such a 
way that the deep median notch which they go to form is even deeper 
and the bristles meet across the median line. 
Further, these pads have the power of transversely approaching 
towards and receding from one another simultaneously, Plate [11] 
XXVIII. figs. 1 and 2. When the animal is on the point of seizing, say 
a leaf of lettuce, the pads are diverged transversely in such a way as to Page 139. 
make the median gap of considerable breadth. Directly the leaf is 
within grasp the lip-pads are approximated, the leaf is firmly seized 
between their contiguous bristly surfaces, and then drawn inwards by 
a backward movement of the lower margin of the lip as a whole. 
The appearance produced by the movements of this peculiar organ 
is very much the same as that of the month in the silkworm and other 
caterpillars whilst devouring a leaf, the mandibles in these insect. 
larve diverging and converging laterally in a very similar manner 
during mastication. 
As to the mechanism of the process, the erectile nature of the lip- 
pads no doubt assists in the manner above indicated. These organs, 
when dilated, form more satisfactory muscularorigins than when flaccid. 
Innumerable transverse muscular fibres connect their basal portions, 
forming the bridge above the median lip-notch, and approximate them. 
They are evidently separated and diverged by the levator labii supe- 
rioris proprius, which is almost entirely distributed, in its insertion, to 
the considerable amount of skin-covered fibro-elastic tissue forming 
the interval between the nares and the lip-margin. . 
With reference to the valvular mechanism for closing the nostrils 
during submersion, it may be mentioned that these circular orifices 
have each a flap valve, which forms the floor or inferior wall of the 
nasal tubes when the animal is breathing, but which rises and com- 
pletely occludes it when closed, as represented in both the figures on 
Plate [11] XXVIII. 
Looking at the living animal generally, the most striking pecu- 
liarity was the sluggishness of its movements. When crossing its 
pond there was uone of the lateral movement of the body so charac- 
teristic of the Seals, All flexions were up and down, the whole trunk 
* “ Mem. Zoolog. Soc. Amsterdam,” 1852, p. 59. 
: x 
