84 THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 
Upon reducing the foregoing measurements to percentages of the total length, 
we find that the distance from the end of the snout to the axilla is 34.3%. In 
Newfoundland specimens of the “Common Finback,” which is closely allied to or 
identical with Balenoptera physalus, as will be seen later, the average for this 
distance is 33.2% of the total length. The length of the pectoral (presumably 
from the axilla) is 9.1%. In nine Newfoundland specimens of the Common Fin- 
back the average is 8.3% The breadth of the pectoral is 2.7% as against 2.9% in 
Newfoundland specimens. 
The color of S. tuberosus is given in the original description as “jet black 
above, white on the belly; sides beautifully marbled by the combination of the 
two colors.” In the story in the American Field, however, the color is thus 
described (see p. 83): “There was a line of demarkation down his side where the 
gleaming white of his belly joined his marbled, grayish black back.” The latter 
description was, of course, from the fresh specimen while the former was probably 
from the dead whale. It is a well-known fact that the gray color in cetaceans 
changes very rapidly after death to black. Taking either description, there is no 
reason for considering S. tuberosus to be other than the Common Finback of North 
American waters. : 
Considering the external characters and proportions as a whole, it seems prob- 
able that the Mobjack Bay specimen was a Common Finback, which is the American 
representative of, or identical with, alenoptera physalus (1). 
There is only one other well-known North Atlantic Finback with which the 
Mobjack Bay specimen can be associated. This is L. borealis. In this species, 
however, the dorsal fin is situated well forward, the pectoral fins are unusually 
small, and the amount of white on the belly is much restricted. None of these 
characters was present in the Mobjack Bay specimen, as far as can be ascertained 
from the published accounts. 
The question of the identity of S. tuberosus cannot be positively decided until 
some of the more important bones of the Mobjack Bay specimen are found and 
examined. In the present article I shall consider it as belonging to the American 
form of B. physalus (1..). 
In order to present the matter fully and fairly, I would add the following: If 
all that Cope stated regarding the skeleton which he described in 1866 is taken 
as really applying to the Mobjack specimen, and all that was added to the original 
description of the exterior in the later papers is interpreted favorably, quite a 
strong case can be made out for identifying S. tuberosus with B. borealis, or at least 
associating it with that species. Thus, while the color of the baleen is not given in 
the original description, in the article of 1866 it is said to be black, which would 
indicate an ally of £B. borealis, and exclude Bb. physalus (.). In the same 
article, the type of S. tuberosus is stated to be “entirely adult at a length of 
43 feet (axial),” which would exclude both B. musculus (L.) and b. physalus 
(L.), but admit B. borealis. Again, in the description of the skeleton, it is stated 
that “the 2%, 32, and 4 cervicals are with large completely united superior 
and inferior lateral processes.” This would confirm the statement that the speci- 
