There was no river, lake, or pond of fresh water to be seen here, but the sea water along the coast abounded with fish, and especially with sharks and rays. On the beach were many kinds of shellfish--mussels, periwinkles, limpets, cockles, oysters--both edible and of the kind which produces pearls. The shore was lined thick with many other sorts of strange and beautiful shells, most finely spotted with red, black, or yellow. There were also green turtle weighing about 200 pounds each, two of which the party caught when they were stranded on shore by the ebbing tide, and which were a most welcome sustenance to the crew, though he speaks of their meat as only being indifferently good. On the other hand, his seamen ate most heartily of the sharks. One of these was 11 feet long, and its maw, or stomach, was like a leather sack, very thick, and so tough that a sharp knife could scarcely cut it. In this they found the head and bones of a "hippopotamus",[61] the hairy lips of which were still sound and not putrefied, the jaw also firm, out of which they plucked a great many teeth, two of them very large, as big as a man's thumb, small at one end, and a little crooked. [61] It was not, of course, a hippopotamus, this creature never having penetrated, even in bygone ages, farther eastwards than India, but a dugong. The dugong is a near relation of the manati, which frequents the tropical rivers and estuaries of West Africa, the West Indies, and South America. The place of the manati is taken in the waters of the Pacific and Indian Oceans by the dugong, which differs from the manati chiefly in having retained in the upper jaw two of the incisor teeth. The manati has only molars, and no front teeth. These incisors of the male dugong develop sometimes into tusks of considerable size--an inferior kind of ivory in the commerce of the Pacific Ocean. The manati, the dugong, and the extinct rhytina of Kamchatka are surviving members of the Sirenian order of aquatic mammals, creatures distantly related to the Ungulate or Hoofed mammals, which adopted an existence in the water ages ago, and gradually lost their hind limbs from disuse. The Sirenians feed only on vegetable food, and the two surviving members of this order, the manati and the dugong, live chiefly on seaweed and the shore vegetation at the mouths of rivers. The manati frequents the coasts of the Atlantic and the dugong those of the Indian Ocean and the Pacific.