ME. A. H. GAEROD ON THE MANATEE. 139 



way as to 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 mouth in the silkworm and other caterpillars whilst devouring a 

 leaf, the-mandibles in these insect larvae 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 satis- 

 factory muscular origins 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 

 superioris proprius, which is almost entirely distributed, in its insertion, to the con- 

 siderable 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 completely occludes it when closed, as represented in both the figures on 

 PI. XXVIII. 



Looking at the living animal generally, the most striking peculiarity was the slug- 

 gishness of its movements. When crossing its pond there was none of the lateral 

 movement of the body so characteristic of the Seals. All flexions were up and do\vn, 

 the whole trunk bending a little in that direction, the base of the tail doing so freely 

 at a clearly marked transverse fold-line in that region. 



An opportunity occurred to me for seeing it out of water, when its pond was drained 

 dry for a short time. From my observation on this occasion it is perfectly evident to 

 me that the Manatee is purely aquatic in habits, and that it never willingly quits the 

 water. When on land it seemed perfectly unable to advance or recede, the only move- 

 ments it performed being that from its belly to its back, and vice versa. In these it 

 made use of its limbs, flexing the body and the tail at the same time. When resting 

 on its belly it seemed extremely uncomfortable, apparently on account of difficulty in 

 breathing, which it is easy to account for on the assumption that the weight of the 

 body being supported on the almost ribless anterior walls of the thorax and abdomen, 

 compressed the abdominal viscera against the lungs, and so greatly diminished the 

 respiratory movements. It would not remain in this position for any length of time, 

 but seemed comparatively comfortable whilst lying quietly on its back, as it did until 

 the inflowing water had refilled the pond sufficiently to allow of its again supporting 

 itself in the water. 



u2 



