134 



THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 



NUMBER OF VERTEBRAE. 



Various European authors have recorded the number of vertebrae in specimens 

 of B.physalus. These specimens were frequently not absolutely complete, and as 

 there is some individual variation, the formulae of different observers show a certain 

 lack of conformity. This affects particularly the caudal vertebrae, the most poste- 

 rior of which are generally lacking in specimens preserved in museums. In the 

 following table a number of records are brought together for comparison in the 

 original form, and on p. 137 the several vertebral formulae are modified in accord- 

 ance with various indications which are discussed on a subsequent page. 



BALJENOPTERA PHYSALVS (L.). EUROPEAN. VERTEBRAL FORMULA. 



1 " It is most probable that the I5th pair has been lost." (Flower, P. Z. S., 1864, p. 415.) 



* " According to Van Beneden, fourteen or fifteen lumbar, though the place of attachment of 

 the first chevron bone in the skeleton indicates but thirteen as belonging to this series." (Flower.) 



"'The number of vertebrae is 61, the last being modelled in wood; but from the character of 

 the 6oth I should say that there ought to be 2 below it." (Flower, P. Z. S., 1864, p. 414.) 



4 "The last pair was quite rudimentary and unconnected with the spinal column." (Flower, 

 P. Z. S., 1869, p. 609.) 



'"The chevron bones appear to be all present. There are 18." (Flower, P. Z. S., 1869, p. 

 608.) 



"There are 61 vertebrae; but the last is elongated and constricted in the middle, as if it 

 really consisted of 2 united." (Flower, /. c.) 



"The last well developed. There may have been a i5th pair." (Flower, /. c., p. 610.) 



""Caudal vertebrae 18, exclusive of those contained in the fin of the tail, which is preserved 

 entire." (Gray, Zool. Erebus and Terror, p. 50.) 



' " At the end of the 25th was found a little conical cartilage. ... It seems to me to 

 represent a 26th caudal." (Delage.) 



10 " The last rib is more elongated than the preceding ribs." (Fischer, C"//. S. O. France, p. 75.) 

 " It is probable that the last caudals were lost during dissection." (Jbid., p. 79.) 



" The i4th pair of ribs, as shown by the photograph, was as long as the preceding pair. 



