182 



THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 



The only two complete formulae are : 



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

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



H. P. Gervais, without explaining how he arrived at the 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 

 \_J3. musculus (L.)] is the following : C. 7, D. 16, L. 15, Ca. 26 = 64." In contradic- 

 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 pairs for both the adult and 

 the foetal Longniddry specimens. 



Gervais, however, insists on sixteen pairs, and further states that the number 

 of lumbars is thirteen, rather 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 from Laponia. Gervais appears to have had in mind an 

 ideal formula which he calls the formula generate, with which the various specimens 

 would be found to agree if studied with sufficient care. I am far from believing 

 that such would be the case, as it seems to be demonstrated that in the majority 

 of cetaceans the number of vertebrae 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 formula does not 

 agree as regards number of caudals with \nsformule general*. 



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

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



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

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

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



So far as adult North American specimens are concerned, we have for com- 

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

 examined and counted the vertebrae of three foetal specimens. The formulae for 

 these and the Ocean City whale are given below. 



It will be remarked that the three formulae from Newfoundland foetuses are 



BALMNOPTERA MUSCULUS (L.). AMERICAN. VERTEBRAL FORMULA. 



1 Positively correct ! 



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



