236 



THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 



MEGAPTERA NODOSA (BONNATERRE). EUROPEAN AND AMERICAN. SCAPULA. 



We find here, beautifully brought out, a gradual increase in the relative 

 breadth of the scapula, with the increase in the size of the skull. Unless the 

 series represented one species, it is hardly likely that this gradation would be 

 obtained. 



The scapulae of the types of M. bellicosa, and M. osphyia, like that of the Tay 

 River (Scotland) whale, show a low, blunt spine, a very narrow prescapular fossa, 

 and a slight elevation on the anterior border (pi. 34, fig. 4 ; pi. 36, fig. 3). The 

 anterior border is nearly straight, though somewhat irregular in the upper three 

 quarters, while the posterior border is evenly concave. A rudimentary coracoid 

 is discernible in the United States specimens, as in the Tay River (Scotland) 

 whale, and in the Greenland skeleton No. 269 in the Brussels Museum. 



RADIUS AND ULNA. 



Struthers has published a figure (87, fig. 6) of the forearm of the Tay River 

 whale, which shows well the shortness and strong curvature of the ulna and the 

 expansion of the radius at the distal end, but hardly gives the impression of mas- 

 si veness which these bones" have. Malm published a figure (after a photograph) 

 of the radius of a specimen in the Stockholm Royal Museum, received from St. 

 Bartholomew Id., West Indies, where it was collected by Dr. Goes (66, fig. 4a). 



This last is comparable with the radius of the type of M. bellicosa, which was 

 also from the West Indies, and probably from St. Bartholomew Id., and was col- 

 lected by Dr. Goes (see p. 97). The two radii are exactly alike, except that the 

 Stockholm specimen appears to be a little narrower at the proximal end. 



The proportion of the breadth of the radius at the distal end to its length in 

 various American and European specimens of Megaptera is as follows : 



Type of M. bellicosa (Phila. Mus.) 41. i % 



St. Bartholomew Island (Stockholm Mus.) 41.0 % ' 



Type of M. longimana (Berlin Mus.) , 40.9 % * 



Greenland (Copenhagen Mus.) 40.3 $ 



Greenland ? (Brussels Mus.) 38.7 $ * 



Type of M. osphyia (Niagara Mus.) 38.2 % 



Tay River, Scotland (Dundee Mus.) 35.8 % ' 



1 The measurements of this radius given by Malm (66, 38) make the breadth at the distal end 

 on ly 33 % f tne length, but it is obvious by examination of the figure that the measurements are 

 incorrect. The above proportion is from the figure, which is after a photographic original. 



2 From the figure. 



