218 SIRENIA 



present at one time. The brain is remarkably simple in structure, 

 its hemispheres exhibiting none of the richness of convolution so 

 characteristic of the Cetacea. The mammary glands of the female 

 are situated just behind and to the inner side of the origin of 

 the pectoral limb. The red corpuscles of the blood are among 

 the largest of those of any members of the class, averaging in 

 diameter, according to Gulliver, . 2 ^ of an inch. 



Manatees pass the whole of their life in the water, inhabiting 

 bays, lagoons, estuaries, and large rivers ; but the open sea, so con- 

 genial to the Cetacea, is quite unsuited to their peculiar mode of 

 life. As a general rule they prefer shallow water, in which, when 

 not feeding, they lie near the bottom, supporting themselves on the 

 extremity of the tail, or slowly moving about by the assistance of 

 the fore limbs, the tips of which are just allowed to touch the 

 ground, and only raising the top of the head above the surface for 

 the purpose of breathing at intervals of two or three minutes. In 

 deeper water they often float, with the body much arched, the 

 rounded back close to the surface, and the head, limbs, and tail 

 hanging downwards. The air in the lungs obviously assists them 

 to maintain this position, acting in the same manner as that in the 

 air-sac of fishes. Their food consists exclusively of aquatic plants, 

 on which they browse beneath the water. They are extremely 

 slow and inactive in their movements, and perfectly harmless and 

 inoffensive. Frequent attempts have been made to keep specimens 

 alive in captivity, and sometimes with considerable success, one 

 having lived in the Brighton Aquarium for upwards of sixteen 

 months. It was fed chiefly on lettuce and endive, but would also 

 eat leaves of the dandelion, sow-thistle, cabbage, turnip, and carrot. 

 From this and other captive specimens some interesting observations 

 upon the mode of life of the animal have been made. One of these 

 is the free use it makes of its fore limbs. From the shoulder-joint 

 they can be moved in all directions, and the elbow and wrist permit 

 of free extension and flexion. In feeding these creatures push the 

 food towards their mouths by means of one. of the hands, or both 

 used simultaneously, and any one who has seen these members thus 

 employed can readily believe the stories of their carrying their 

 young about under their arms. Still more interesting and quite 

 unique among mammals is the action of the peculiar lateral pads 

 formed by the divided upper lip, thus described by the late Pro- 

 fessor Garrod : " These pads have the power of transversely 

 approaching towards and receding from one another simultaneously 

 (see Fig. 73, A and B). 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 make a 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 



