THE WHALES, DOLPHINS AND MANATEES 343 



quantity of the water containing its minute marine food, and then 

 closing the mouth the liquid escapes, and the small organisms are 

 entangled in the hairy meshes of the ends of the whalebone or 

 baleen plates. 



The Manatees (Sirenia) are a small group of marine mammalia, 

 which, on account of their singularly isolated position, are of peculiar 

 interest to the zoologist. Partly from their aquatic habit and 

 some outward resemblances, they were classed by Cuvier among 

 the whales, but Illiger signalised and denned them as a separate 

 sub-order, the Sirenia, with an organisation differing distinctly 

 from that of the whales ; while later de Blainville strove to show 

 that they possessed certain elephant-like structures which entitled 

 them to close proximity to these creatures. Although still placed 

 in the immediate vicinity of the whales, it is now generally ad- 

 mitted by zoologists that the likenesses which they undoubtedly 

 show to the Cetacea are of an adaptive kind and related to their 

 mode of life. Among the general characters of the Sirenia is a 

 long, compact, cylindrical body, without a back fin, narrowing 

 towards the tail, which terminates either whale-like, in forked 

 flukes, or beaver-like, in a great flat expansion. The fore -limbs 

 are encased, flat, and flipper-like, exceedingly flexible, and more 

 completely formed than in the whales. The extinct and fossil 

 Halitherium alone is known to have possessed rudiments of hind- 

 limbs, though pelvic bones are present in all. The skin is dark, 

 elephant-like, tough, and may be sparsely covered with hair, or 

 smoothish and whale-like. The two mammas are on the breast 

 close to the armpits. The Sirenia are animals of slow habit, and 

 are most inoffensive, feeding solely upon aquatic vegetation. 



Steller's Rhytina (Rhytina Stelleri), sole representative of the 

 genus, is now extinct. When the Russian, Behring after whom 

 the Straits are named first visited that region and the neigh- 

 bourhood of Kamtschatka, there existed a huge animal, of which, 

 under the name of Manatee, or Northern Sea Cow (Vacca marina), 

 the naturalist Steller, who accompanied him, gave a classical 

 account. It had a small oblong head, a full bristly snout, and a 

 dark-coloured body protected by a rugged, gnarled, warty, hairless 

 skin. The four limbs were quite short and stumpy, and the tail 

 ended in a horizontal, stiff, half-moon-shaped, narrow fin-blade 

 fringed with a fibrous, whalebone-like material. It had no teeth, 



