252 ALLEN: NEW ENGLAND WHALEBONE WHALES. 



vertebrae is usually 64, but varies one more or less than this. The neck vertebrae are 

 normally separate. 



The second and third ribs have well developed capitular processes, and the fourth has a 

 smaller one, extending in toward the vertebral column. These are the vestiges of the heads 

 of the riljs which in other mammals form the chief articulation with the centra of the vertebrae 

 throughout the series. In the Balaenopterae this, inner articulation has been lost and the 

 ribs are loosely attached by their tubercles only, at the tips of the lateral processes of the verte- 

 brae. In the skeleton at Ostend described by Dubar the first rib has two heads — as occa- 

 sionally in the Common Finback. 



The sternum is probably subject to much the same variation as that of the latter species, 

 though the few figured specimens are somewhat similar: namely a transverse plate, with a 

 small protuberance at its front edge and a longer one behind that extends between the lower 

 ends of the first pair of ribs. 



The scapula is fairly characteristic. Though in general much Uke that of the Common 

 Finback, its upper outline is less flattened, making thus a more even arc. The acromion pro- 

 cess is slightly larger, and expanded at the end. The coracoid process is decidedly thicker 

 and nearly half the length of the acromion. 



The radius in the Blue Whale "is remarkable for its breadth, and the ulna for its strong 

 curvature" (True) as compared with these bones in the Common Finback. In the New Jersey 

 specimen ((iO feet long) the radius measured 32.5 inches (0.S2 m.) in length and 10 inches 

 (0.25 m.) in breadth at the distal end. The ulna was 34.5 (0.87 m.) long and 8 inches 

 (0.20 m.) in breadth at the distal end. 



The number of phalangeal bones probably varies within slight limits. The greatest number 

 recorded is that given by True for a foetus he dissected, namely, 5, 8, 7, 4 for the respecti\e 

 digits. In six other specimens recorded by European authors, the variations are: 14; II 5 

 to 7, IV 5 to 7, V 3 to 4. 



The peh'ic bones seem slightly more reduced than in the Common Finback, though 

 of much the same general shape. Lonnberg (1910, p. 10) has figured one of the peh'ic bones 

 in a Blue Whale from the South Atlantic. He found no trace of the rudimentary femur, though 

 on account of the hmnaturity of his specimen it is Ukely that it had not ossified. Dubar (1828) 

 figures the pelvic bones of the Ostend Blue Whale, but the representations are poorly executed; 

 this author likewise omits reference to any rudimentary femur. 



Habits. 



The Blue Whale is less social than the Common Finback, and does not seem to gather 

 into large schools. Commonly it is seen singly or in pairs. Whales, when travelling in pairs, 

 nio\-e in unison, rising and diving together with much regularity. As with other large whales. 



