BEAKED WHALES, FAMILY ZIPHIID-E TRUE. 



External dimensions of Berardius bairdii and B. arnuxii. 



67 



o "Length of gape." 



The measurements of these specimens of bairdii agree well together. The 

 specimen of arnuxii appears to have had narrower flukes, shorter pectoral fin, and 

 a rather higher dorsal fin, situated farther forward than in bairdii. Measurements 

 of a larger number of specimens might show that some or all of tliese differences of 

 proportion are elusive, but it will be observed that in the Wellington specimen of 

 arnuxii, recorded by Doctor Haast, the breadth of the flukes is only 21 per cent of 

 the total length. The pectoral fin is said to be only 19 inches long, or onty 5.2 per 

 cent of the total length, but the manner of taking tlie measurement is not mentioned. 



As regards size, the largest specimen of B. arnuxii of which I find record is the 

 type specimen. This was 32 feet long, and the skull 1,400 mm., or about 55 inches 

 long. This appears to have been an adult male. The CentervUle specimen of 

 bairdii, which was an adult male, was about 41 feet long, and the skull 1,532 mm., 

 or about 60 inches long, while the adult female from St. George Island was 40 feet 

 2 inches long and the skull 56 inches. Although the total length of the specimens 

 of bairdii is so much gi'eater, it will be observed that the length of the skull, while a 

 little greater, absolute!}' fails to measure up to the proportions found in arnuxii. 

 It might be suspected on this account that the external measurements of bairdii 

 were exaggerated, but that such is not the case will appear from an examination of 

 the measurements of vertebrae given on page 75. It is evident that the specimens 

 of bairdii are far more massive in all parts of the skeleton than the specimen of 

 arnuxii there cited. The same relations will be found upon comparing measure- 

 ments of the specimen of arnuxii figured by Van Beneden and Gervais." The 

 truth appears to be that bairdii is a much larger species, but tliat the skull is 

 considerably smaller relatively. 



" Ost^ographie des Cetac^s, pi. 23 bis. 



