298 THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 



considerable numbers of specimens from the regions mentioned. Such opinions 

 have,' of course, a certain interest and value, but knowledge will not be greatly 

 increased without the study of new material. 



Even should it be demonstrated that the species of large whalebone whales are 

 cosmopolitan, it does not follow that the individuals constituting these several 

 species range throughout the globe. The probabilities are much against such 

 world-wide movements, and in the case of the Right whales it appears to have been 

 demonstrated by Maury that individuals do not cross the equator. In this latter 

 case, and perhaps in others,' it would appear that the study of the migrations of 

 separate groups of individuals, or schools, can be carried on profitably without 

 regard to the general facts pertaining to the distribution of the species as a whole. 



The following diagnoses of North Atlantic species are intended to summarize 

 the observations of earlier writers both American and European, as well as those 

 detailed in the preceding pages. The diagnosis of Balcvnoptera borealis is based on 

 Collett's admirable account of that species (21). 



BALDEN A GLACIALIS Bonnaterre. 

 Black whale, Nordcaper, or Biscay whale. Plate 50, fig. 2. 



Form massive. Head very large. Rostrum narrow and curved, with a pro- 

 tuberance near the anterior end (" bonnet "). Blowholes elevated and followed by 

 a distinct depression. Lower lip very large, oblong, the free margin more or less 

 sinuous. 



Pectorals very broad, short, with a convex posterior margin and pointed tip. 



Color black throughout, or with more or less white on the throat and breast 

 in some individuals. 



Rostrum of skull very long and narrow; the anterior half strongly curved. 

 IntermaxillaB broad, occupying nearly the whole upper surface of the rostrum. 

 Nasals very large, broad, oblong. The free anterior border w-shaped. Orbital 

 process of frontal very narrow, somewhat tubular, and only moderately bent back- 

 ward, the orbital border very narrow, oblique. Occiput broad, with convex sides. 



Sternum broadly and irregularly triangular. Scapula broader than high ; 

 broad near the base. Vertebral formula: C. 7, D. 14, L. 11 (10-12), Ca. 23 (-26). 

 Total 55 (-57). 



MEGAPTERA NODOSA (Bonnaterre). 

 Humpback. Plate 50, fig. 1. 



Form massive and peculiarly ungraceful, size moderate. Head flat and obtuse. 

 Abdominal ridges few and broad, 14 to 30. Average total length, 48 feet ; 

 maximum, 55 feet. 



Pectorals, from head of humerus, 32 per cent, of total length ; lanceolate, with 

 extremity recurved ; anterior margin with ten or eleven very prominent sinuosities 

 corresponding to the joints of the manus ; posterior margin convex proximally, 

 concave distally, with several small sinuosities at the extremity. 



