GENERAL CHARACTERS. 569 



Mode of Life Although the manatis and dugongs never leave the water, and 



are as well adapted for an aquatic life as the Cetaceans, yet they 



cannot swim in the rapid manner characteristic of many of the latter, and are 



never found inhabiting the open sea. On the contrary, they frequent shallow seas 



and bays, lagoons, estuaries, and large rivers. As regards their food, these animals 



are entirely herbivorous ; browsing upon sea- weeds or other aquatic plants growing 



beneath the surface of the water. They are slow and sluggish in their movements, 



while in disposition they are harmless and inoffensive, and appear to be endowed 



with but a comparatively small amount of intelligence. 



Both dugongs and manatis produce but a single offspring at a birth, which is 



attended with assiduous care by its parent. When suckling, the females raise their 



heads and breasts above the water, and exhibit the young clinging to them, and 



partially supported by their nippers ; and there can be little doubt but that this 



habit has given origin to the legendary mermaid. In describing the dugong, Sir 



Emerson Tennent wrote as follows concerning this point: — "The rude approach 



to the human outline observed in the shape of the head of this creature, and the 



attitude of the mother when suckling her young, clasping it to her breast with one 



flipper, while swimming with the other, holding the heads of both above water ; 



and when disturbed, suddenly diving and displaying her fish-like tail, — these, 



together with her habitual demonstrations of strong maternal affection, probably 



gave rise to the fable of the mermaid ; and thus that earliest invention of mythical 



physiology may be traced to the Arab seamen and the Greeks, who had watched 



the movements of the dugong in the waters of Manaar. Megasthenes records the 



existence of a creature in the ocean near Taprobane [Ceylon], with the aspect of a 



woman ; and iElian, adopting and enlarging upon his information, peoples the seas 



of Ceylon with fishes having the heads of lions, panthers, and rams, and, stranger 



still, Cetaceans in the form of satyrs. Statements such as these must have had 



their origin in the hairs which are set round the mouth of the dueronff, somewhat 



resembling a beard, which /Elian and Megasthenes both particularise from their 



resemblance to the hairs of a woman." The belief in the existence of mermaids 



was firmly credited by the early Portugese and Dutch voyagers to the East. 



The living*; members of the order, which p'enerally associate in 

 Distribution. & . 



small herds, frequent the coasts and larger rivers on both sides of tin- 

 Atlantic, and also those of the Red Sea, the Indian Ocean, parts of the Bay of 

 Bengal, and Australia. The northern sea-cow was, however, an inhabitant of the 

 cold regions of Behring Sea; and during the Tertiary period Sirenians were distri- 

 buted over the greater part of the globe. The group is. therefore, evidently a 

 waning one. From their herbivorous habits and the structure of their molar teeth 

 the suggestion naturally arises that the Sirenians are connected with the Ungulates; 

 and the resemblances of their teeth are nearer to the Even-toed than to the < )<id-toed 

 section of that order. The retention of five toes by the Sirenians seems, however, to 

 indicate that if they are really connected with the Ungulates, they must have 

 diverged from that group at a very early period of its existence. 



It has been very generally considered that each of the three 



genera of Sirenians that have existed during the historic period is 

 entitled to constitute a family by itself. The whole are, however, so nearly allied, 



