THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 241 
black and white—and the amount and distribution of these colors are variable to 
the same extent in specimens from the eastern and western Atlantic. 
3. The measurements of external proportions of the body and fins show a 
substantial agreement, except as regards the spread of the flukes, in which there is 
an unexplained variability. 
4. The abdominal folds agree in number, size, and especially in arrangement. 
5. The dermal tubercles on the head agree well in number, size, and general 
arrangement, though there is a large individual variation. 
6. There is no constant difference in the shape of the dorsal fin between the 
American and European Humpbacks, unless it be that the tip is thicker in Green- 
land specimens. 
7. The pectoral fin agrees in length, breadth, and especially in the protuber- 
ances of the margins. 
8. ‘The flukes are alike in form, with a possible difference in spread. 
9. The outline of the caudal peduncle or “small” is alike in Newfoundland and 
Norwegian specimens. 
10. The skeleton agrees closely in the number of vertebrze and the formula for 
the same; in the proportions of the skull and of the bones of the limbs. The 
Greenland Humpback, however, appears from Eschricht’s figure to have smaller 
nasals than the others, and more deeply emarginated frontal orbital processes, but 
there is a strong presumption that the figure is inaccurate. 
Considering the difficulties encountered in instituting exact comparisons be- 
tween data recorded at different times by different observers, the agreement is 
sufficiently close to justify the opinion that the Humpback whales of the North 
Atlantic are all referable to the same species. In other words, the differences between 
the nominal species JZ. nodosa, longimana, osphyia, bellicosa, americana, ete., are not 
substantiated. 
Although the type-skeleton of JZ. osphyia Cope, which in the foregoing pages 
has been currently treated as representing the common Humpback of the western 
North Atlantic, shows no differences which would render such treatment unwar- 
ranted, it seems to me desirable to consider a little further the differences by which 
Cope supposed it could be separated from JZ. longimana. 
Cope compares his species with J/. dongimana as described in the works of 
Rudolphi, Gray, and Flower, and concludes that it is different for the following 
reasons : 
1. MW. osphyia has long inferior lateral processes in the posterior cervical 
vOM hed 
The atlas is a parallelopiped in form, the transverse processes are elevated, 
and ae is an “internal process.” 
3. The cranium is broader in proportion to its length than in JZ. longimana, 
and shorter in proportion to the total length of the skeleton. 
The pectoral fins are shorter. 
The vertebrze and chevrons are less in number. 
é The first pair of ribs is very broad. 
7. The spines of the lumbar vertebra are much higher. 
oe 
