352 BREAST BONE CHAP. 
vertebra, though hardly at all marked, is nevertheless really 
present and developed from a bony centre of its own, as in other 
mammals. The dorsal and lumbar vertebrae are, of course, to be 
distinguished by the presence of ribs attached to the former; but 
Fic. 186.—Section through middle 
line of united cervical vertebrae 
of Greenland Right Whale (Ba/- 
aena mysticetus). x4. a, Arti- 
cular surface for occipital condyle ; 
é, epiphysis on posterior end of 
body of seventh cervical vertebra ; 
sn, foramen in arch of atlas for 
first spinal nerve ; 1, arch of atlas ; 
2, 3,4, 5, 6, conjoined arches of 
the axis and four following verte- 
brae ; 7, arch of seventh vertebra. 
(From Flower’s Osteology.) 
as there is only a rudimentary pelvis, not attached to the 
vertebral column, no sacral region can be detected. The caudal 
vertebrae are to be recognised by the V-shaped chevron bones 
below. 
Fic. 187.—A, Sternum of Greenland Right Whale (Balaena mysticetus). x 5. B, 
Sternum of Common Rorqual or Fin Whale (Balaenoptera musculus). x jy. 
(From Flower’s Osteology. ) 
The sternum in the Whale tribe is much more modified in the 
Whalebone Whales than in the Odontocetes. In the latter it is 
made up of several pieces, as in other mammals, which often, 
however, become coalesced. In the Mystacoceti this bone is a 
single piece, to which only one pair of ribs is attached, and its 
