THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 293 



Scarnrnon's measurements of B. davidsoni, show a very close agreement with those 

 of Sir Win. Turner's specimen from Granton, Scotland, except in theposition of the dor- 

 sal fin. In Scammon's specimen the distance from the tip of the snout to the posterior 

 margin of the dorsal fin is 66.6 % of the total length, while in the Granton specimen it 

 is 70 $, and in other European specimens, from 71 % to 74$. This difference would 

 be of importance if substantiated, but a study of Scammon's measurements shows 

 that it is due to an error. He states that the genital opening is slightly behind the 

 anterior edge of the dorsal fin. We may presume, therefore, that the latter is about 

 6 in. in advance of the former, which is 9 ft. 6 in. from the notch of the flukes, or 17 

 ft. 6 in. from the tip of the snout. The anterior edge of the dorsal fin is, therefore, 

 17 feet from the tip of the snout, and as its base is 2 ft. 4 in. long, the posterior edge 

 would be 19 ft. 4 in. from the tip of the snout, which is 71.6 % of the total length. 



That this calculation is substantially correct is shown by the fact that in the 

 fcbtus from the same specimen, the measurements of which are given by Scammon, 

 the distance of the posterior margin of the dorsal from the tip of the snout is 71.2 % 

 of the total length. The dorsal fin in B. davidsoni, is, therefore, situated as in 

 B. acuto-rostrata. 



Mr. W. H. Dall, in the appendix to the Marine Mammals (82, 304, 305) gave the 

 following measurements of a skull of unknown locality, presented to the museum of 

 the California Academy of Sciences, by Mr. Merrill : 



BALj&MOPTERA DA VIDSONI SCAMMON. SKULL. 



In. and looths. 



Length of skull in straight line 48.00 



Breadth of condyles 4-So ? 



Breadth of ex-occipitals (to outer edge of suture) 17.00 



Breadth of squamosals 27.00 



Height of foramen magnum 2.00 



Length of supra-occipital 13.00 



Length of articular process of squamosal, antero-posterior 8.00 



Length of orbital process of frontal, right to left 10.00 



Breadth of orbital from curved border of maxillary to hinder edge of orbital process of 



frontal 9.00 



Breadth of orbital at upper surface of outer end 6.50 



Nasals, length 4.50 



Nasals, breadth of the two at posterior end r.oo 



Nasals, breadth of the two at anterior end 2.50 



Length from curved border of maxillary to tip of beak 3.oo 



Length of maxillary 33- 



Projection of premaxillary beyond maxillary 1.50 



Breadth of maxillaries at hinder end 6.00 



Breadth of maxillaries across orbital processes 1 2.50 



Breadth of beak at base (curved) 16.50 



Breadth of beak at its length from base (curved) 1 2.00 



Breadth of maxillary at J its length from base (curved) 2.50 



Breadth of premaxillary at same point (curved) i.oo 



Breadth of beak at middle (curved) 9.00 



Breadth of maxillary at middle (curved) 2.50 



Breadth of premaxillary at middle (curved) 1.50 



