106 CETACEAN GALLERY. 



filled with oil. In the vertebral column the region of the neck 

 is remarkably short and incapable of motion, and the vertebrae, 

 originally seven in number, as in other mammals, are in many 

 species more or less fused together into a solid mass. None of 

 the hinder vertebras of the body are united together to form a 

 " sacrum " or to join the pelvis, as in mammals in which the hind 

 limbs are fully developed. The lumbar and caudal vertebrae are 

 numerous and large, and capable of very free motion in all direc- 

 tions. Beneath the latter are large chevron bones which pro- 

 ject downwards, and give increased surface for the attachment of the 

 powerful muscles that move the tail. There are no bones sup- 

 porting the lateral C( flukes " of the tail or the dorsal fin. 



The skull is modified in a peculiar manner. The brain-case is 

 short, high, and broad, almost spherical in fact. The nostrils open 

 upwards, immediately in front of the brain-case, and before them 

 is a more or less horizontally prolonged beak or "rostrum," ex- 

 tending forwards to form the upper jaw or roof of the mouth. In 

 detail the form of the skull varies much in different groups. 



There are no collar-bones or clavicles. The upper arm-bone or 

 humerus is freely movable on the scapula or blade-bone at the 

 shoulder-joint ; but beyond this the articulations of the limb are 

 imperfect, flattened ends of the bones coming in contact with each 

 other, with fibrous tissue interposed, allowing of scarcely any 

 motion. The two bones of the forearm (the radius and ulna) are 

 distinct and very much flattened, as are all the bones of the hand. 

 There are usually five fingers, though sometimes the first, or that 

 which corresponds to the thumb of man, is wanting. The pelvis 

 or hip-bone is represented by a pair of elongated slender bones, 

 suspended below, and at some distance, from the vertebral column, 

 in the region of the loins. As these bones are in the living animal 

 concealed in the flesh and not connected with the spinal column, 

 they are often lost in preparing the skeletons, and hence are 

 absent in many of the specimens in the Gallery. To the outer 

 side of these, in some Whales, small bones are attached which 

 represent the bones of the limb proper. In the great skeleton of 

 the Rorqual (Balanoptera musculus), at the further end of the 

 Gallery, a little nodule of bone, scarcely larger than a walnut, has 

 been fortunately preserved. It is the rudiment of the thigh-bone 



