182 



THE WHALEBONE WHAXES OF THE WESTERN NORTH ATLANTIC. 



The ouly two complete formulae are : 



C. 7, D. IS, L. 15, Ca. 26 = 63, — Gothenburg. 

 C. 7, D. 16, L. 15, Ca. 26 = 64,— Kiel. 



H. P. Gervais, without explaiuiug bow he arrived at tiie fact, remarks {51, m. 23), 

 that " the vertebral formula given hitherto by the authors who have had occasion 

 to observe and describe skeletons belonging to the species which occupies us 

 [i?. musculm (L.)] is the following : C. 7, D. 1 6, L. 15, Ca. 26 = 64." In conti-adic- 

 tion it will be observed from the preceding table that the Hull Museum specimen, 

 described by Flower, and the Sylt Id. specimen, described by Mobius, are the only 

 ones reported as having sixteen pairs of ribs. Sir William Turner, than whom 

 there is no more competent authority, reports fifteen paii's for both the adult and 

 the foetal Longniddry specimens. 



Gervais, however, insists on sixteen pairs, and fui'ther states that the number 

 of lumbai'S is thirteen, i-ather than fifteen. He bases this latter assertion on an 

 examination of a skeleton from Cape Horn (which he assigns to this species) and 

 two skeletons and a foetus fi-ora Lapouia. Gervais appears to have had in mind an 

 ideal formula which he calls t\\e formvle generate, with which the various specimens 

 would be found to agi-ee if studied with sufticient care. I am far from believing 

 that such would be the case, as it seems to be demonsti-ated that in the majority 

 of cetaceans the nunil)er of vertebra; and their division into dorsals, lumbars, and 

 caudals is subject to a certain amount of variation. Even in the specimen from 

 Cape Horn which Gervais assigns to B. musculus the vertebral foi'mula does not 

 ao-ree as regards number of caudals \vith his formule generale. 



Supposing Turner, Flower, Gervais, Malm, and Mobius all to have been correct, 

 we should have a variation for the European £. musculus, as follows : 



(1) C. 7, D. 16, L. 13, Ca. 28 = 64. 



(2) C. 7, L). 16, L. 15, Ca. 26 = 64. 



(3) C. 7, D. IS, L. 15, Ca. 26 = 63. 



So far as adult North American specimens are concerned, w^e have for com- 

 parison only the Ocean City whale, but while at the Newfoundland Station I 

 examined and counted the vertebras of thi-ee fcetal specimens. The foi'mulae for 

 these and the Ocean City whale are given below. 



It \\\\\ be remarked that the three formulae fioni Newfoundland ftetuses ai'e 



BAL^NOPTERA MUSCULUS (L.). AMERICAN. VERTEBRAL FORMULA. 



Positively correct 



'Perhaps fifteen lumbars should be counted. It is uncertain. 



