THE WHALEHONE WHALES OF THE WESTERN NORTH ATLANTIC. 241 



black aiul white— and tlie iimomit and distiibutiou of these colors are variable to 

 the same extent in specimens from the eastern and western Atlantic. 



3. The measurements of e.\tei-nal proportions of the body and fins show a 

 substantial agreement, except as regards the spread of the flukes, in which theiv i< 

 an unexplained variability. 



4. The abdominal folds agree in number, size, and especially in anangement. 



5. The dermal tubercles on the head agree well in number, size, an<l general 

 ai'raugement, though there is a large individual vaiiation. 



G. Theie is no constant dilference in the shape of the dorsal fin Ix-tween the 

 American and European Hiuupbacks, unless it be that the ti[) is tliicker 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 i)e(luncle or " small " is alike in Newfoundland and 

 Norwegian specimens. 



10. The skeleton agrees closely in the number of vertebr* and the formula for 

 the same; in the pi'oportions of the skull and of the bones of the limbs. The 

 Greenland Humjiback, howevei', appears from Eschriclit's figure to have smaller 

 nasals than the othei's, and more deeply emai-ginated frontal orbital processes, but 

 theie is a strong pi-esuuiption 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 ai'e all referable to the same species. In other words, the differences between 

 the nominal species M. 7iodosa, longimana, osphyia, helUcom, americaiia, etc., are not 

 substantiated. 



Although the type-skeleton of M. osphyia Cope, which in the foregoing pages 

 has been cunently 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 whicli 

 Cope supposed it could be separated from M. longimana. 



Cope compares his species with M. longimana as described in the works of 

 Rudolphi, Gray, and Flower, and concludes that it is different for the following 

 reasons : 



1. M. osphyia has long inferior latei-al processes in the posterioi- cervical 

 vertebras. 



2. The atlas is a parallelepiped in form, the transverse processes are elevated, 

 and there is an "internal process." 



3. The ci-anium is broader in proportion to its length than in AI. longimana, 

 and shorter in pi'opoition to the total length of the skeleton. 



4. The pectoral fins are shoi-tei'. 



5. The vei'tebne and chevrons aie less in number. 

 (). The first jiair of rii)s is very broad. 



7. The spines of the lumbar vertebrae are much higher. 



