THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 



295 



In spite of the correspondence in general proportions between two Pacific 

 skulls and the Norway and Massachusetts skulls, my associates, Dr. L. Stejneger 

 and Mr. G. S. Miller, Jr., who examined them with me, while side by side in one of 

 the halls of the Museum, pointed out certain characters in which the two Atlantic 

 skulls appeared to them to differ from the two Pacific skulls. The principal of 

 these were (1) that the nasal processes of the maxillse were bent toward the median 

 line much more strongly in the Pacific than in the Atlantic skulls, and (2) that the 

 orbital process of the maxillae was shorter and thicker in the former than in the 

 latter. The characters will be seen by comparing the figures on plates 22 and 23. 

 I also noted that in the Pacific skulls the vomer appeared to descend more opposite 

 the anterior end of the palatines, giving a stronger curve to the inferior profile of 

 the cranium, and that the palatines were broader posteriorly. I have endeavored 

 to bring out some of these differences in the last three measurements of the fore- 

 going table. These measurements reduced to percentages of the total length of 

 the skull are repeated below : 



BALJENOPTERA ACUTO-ROSTRATA LAC. AND B. DAVIDSONI SCAMMON. SKULL. 



It would appear from the foregoing that the vomer is deeper in the Pacific 

 skulls, but the proportional length of the orbital process of the maxilla does not 

 differ materially in the Norway and Pacific skulls. The breadth of this process, as 

 shown by plates 22 and 23, is greater in the Pacific skulls than in the one from 

 Norway. This greater breadth, however, is approximated in Eschricht's figure of 

 an adult skull from Norway (37, pi. 9, fig. 1). 



If any of these differences prove constant on examination of a larger number 

 of specimens, it will probably be the greater depth of the vomer and the bend- 

 ing inward of the nasal process of the maxilla. As regards the latter, Eschricht's 

 and Capellini's figures of European skulls present a substantial agreement with our 

 skulls from Norway and Massachusetts. 



1 Type of B. davidsoni. 



' 2 in. added for breakage. 



