THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 99 



Cope's estimate of the total length may not have been considerably too small. At 

 all events it is only an estimate, and hence this particular relation is not a good one 

 to employ as an aid in determining the identity of the species. 



In the skull of bellicosa, the anterior margin of the orbital plate of the frontal 

 is nearly straight, as stated by Cope, and, hence, offers a contrast to other Mega/p- 

 tera skulls I have examined, in all of which the margin is quite concave. 



In regard to the first rib of bellicosa Cope remarks : " If Rudolphi's figures [of 

 M. longimana] are correct, the first rib is broader in the present animal, but the 

 figure may be inaccurate." The width at the distal end in bellicosa is given as 7 

 inches. Struthers gives 7-^- inches for the right rib in his skeleton of longimana, 

 and only 5 inches for the left rib. In skeleton No. 21492, both ribs of the first 

 pair measure 5 inches at the distal end. It thus appears that there may be equality 

 or marked inequality in the same individual, and hence the width of the rib, unless 

 a considerable number of individuals can be compared, is not a character to be 

 relied upon. 



Finally, Cope states that the pectoral fin of betticosa was black externally, but 

 " entirely white in Arctic Megaptera." This is not, of course, from his own observa- 

 tion. The "Arctic Megaptera" Cope had in mind is doubtless M. longimana, but 

 Cocks has shown (17) that in the Humpbacks killed at the Norwegian whaling- 

 stations the color of the outside of the pectoral varies greatly. It may be entirely 

 black, or only the proximal fourth black, or "black for only a very short distance 

 at the proximal end," etc. Of three fresh specimens examined at Snook's Arm, 

 Newfoundland, Aug., 1899, two (a male and a female) had the upper surface of 

 the pectoral entirely white, except for a small area proximally, and a narrow poste- 

 rior margin, where it was black. In the third specimen (a female), the proximal 

 half was all black, and the distal half black and white mottled, the black predomi- 

 nant. There is, therefore, no constancy in the coloring of the pectoral, as, indeed, 

 is the case also with the body, and the details of a single individual cannot be 

 considered as having much importance. 



It appears from the foregoing review that of the characters assigned by Cope 

 to M. bellicosa, the shape of the anterior margin of the orbital process of the frontal 

 is the only one which merits consideration. That this is not likely to be of impor- 

 tance seems probable from the fact that a further comparison of the type with 

 specimens of the common Humpback of the Atlantic coast of North America, as 

 detailed in a subsequent chapter, fails to disclose correlated distinguishing charac- 

 ters, while the agreement extends to many parts not mentioned by Cope. I feel 

 justified, therefore, in treating M. bellicosa as representing the common Humpback 

 and not a distinct species. 



The following are actual measurements of the type-skeleton of M. bellicosa, 

 according to Cope's system, made by me in 1900, to which are added Cope's 

 original measurements : 



