Near the pavilion is a skeleton (fig. 45) of an interesting animal, the Northern Sea-Cow (_Rhytina gigas_ or _stelleri_), the last resort of which was Bering Island in the North Pacific, where it was completely exterminated towards the close of the eighteenth century. In the same case is placed the skeleton of a smaller allied animal, the _Halitherium_, from the Oligocene of South Germany. These, with their existing representatives, the Manatee and Dugong, constitute the order Sirenia, aquatic Mammals of fish-like form, presenting considerable external resemblance to Cetacea (Whales and Dolphins), but differing in many points of structure and habit. All the exhibited specimens of the group, both living and extinct, are shown in this gallery. [Sidenote: Fossil remains of Man.] The wall-cases on the south side (right on entering) contain typical series of chipped and polished flint implements of human workmanship, and also remains of Man found, under circumstances which may justify the appellation of “fossil,” in caves or Pleistocene deposits, associated with the bones of Mammals either completely or locally extinct. Then follow in systematic order the bones and teeth of the other Primates, the Carnivora, Ungulata, and Sirenia. [Illustration: FIG. 45.--SKELETON OF THE NORTHERN SEA-COW (_Rhytina gigas_ or _stelleri_). From Bering Island. Length of specimen, 19 feet 6 inches.] [Sidenote: Elephants and Ruminants.] The greater part of the north side of the gallery is devoted to the exhibition of the remains of Proboscidea (Dinotheres, Mastodons, and Elephants), as well as teeth and skulls of the two existing species of Elephants. The forerunners of the Proboscidea from the Eocene strata of Egypt, as represented by _Palæomastodon_ and _Mœritherium_, are of special interest. Attention may likewise be directed to the skull of the gigantic Ruminant _Sivatherium_ (fig. 46), from the Siwalik deposits of Northern India, an ally of the living African Okapi (p. 41), with which it is connected by _Helladotherium_ of the Grecian Tertiary deposits; another still more nearly allied type being _Samotherium_, from the Isle of Samos, of which a skull (fig. 47) is exhibited. [Illustration: FIG. 46.--SKULL OF _Sivatherium giganteum_, an Extinct Ruminant from the Pliocene Deposits of the Siwalik Hills, India. About 1/13th natural size.] [Sidenote: Edentates.]