204 



THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 



BAL.JKNOPTEKA ACUTO-BOSTBATA LAC. EUROPEAN AND AMERICAN. SCAPULA. 



The Norwegian skeleton in the National Museum is the only one which 

 breaks the regular gradation. 



The scapula of B. acuto-rostrata, appears to have been seldom figured. Esch- 

 richt's figure, copied above, is not very satisfactory, and the figure in the Oste'o- 

 graphie appears distorted. Outlines of these figures and of the scapulae of the 

 Massachusetts and Norway specimens in the National Museum are shown in text 

 figs. 53 to 56. The scapulae of the last two are also figured on pi. 27, figs. 3 and 4. 



In respect of number of phalanges the skeletons preserved in museums are 

 usually defective, and no accurate comparisons can be made. The numbers derived 

 from examination of foetal specimens are far more satisfactory, but the two series 

 are, of course, hardly comparable. The enumerations of various cetologists for B. 

 acuto-rostrata are as follows : 



BALMNOPTERA ACUTO-BOSTBATA LAC. EUROPEAN. PHALANGES. 



For the skeleton from the coast of Massachusetts, No. 20931, which is that of a 

 young animal, the formula is as follows : Left, 3. 6. 6. +. ; right, 2 +. 7. 5 (+!) 1 +. 



STERNUM. 



The sternum of the Massachusetts skeleton has not at all the Latin-cross form 

 characteristic of adult specimens of JB. acuto-rostrata, but it represents, doubtless, 

 an immature stage leading up to that form. The anterior moiety is short and 

 broad, with a rounded contour ; on each side is a tubercle, or rudimentary arm ; 



