142 



THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 



16045 from Cape Cod, Mass. (See pi. 7, fig. 4.) Tbe Cayeux specimen, cited by 

 Fischer as yoimg, appeal's to be exceptional in having the anterior border entire, 

 with a vacuity below it, and the stem and wiugs scarcely differentiated. A close 

 approximation to the normal form of the immature steriuim is perpetuated in the 

 adult in Malm's Fiumark specimen, and Sars's Christiania Museum specimen. The 

 latter leads to the moi-e extraordinary adult form exhibited by the Groix Id., Albany 

 (N. Y.) museum, Rochester (N. Y.) museum, and Langruue specimens, in which 

 the anterior emargination is generally pronounced and the wings long and pointed. 

 A quite different adult foi-m is shown in the Vlieland Id., Herault, Borselaer 

 (Scbelde E,.), Bayonne, and Cambi'idge (Mass.) museum specimens, in which the 

 anterior border is convex, forming a foui'th projection and converting the ti'efoil 

 into a quatrefoil. This is cari'ied to an extreme in Struthers's Peterhead specimen, 

 in which the stem is aborted, and in the St. Cyprien specimen, in which the anterior 

 portion is very large, with a straight mai'gin and a vacuity within it. Finally, we 

 have a variation in which the anterior and lateral limbs are merged together, as 

 shown in the Falmouth and Cambridge (Mass.) museum specimens. 



In all these variations the American specimens run parallel with the European 

 ones. 



Fig. 33. 



Fio. 35. 



Fig. 34. Fig. 36. 



scapula of bal^soptera physalus (l.). american and european. 



Fig. 33. — Lofoten Ids., Norway. Jr. (From Sars.) Fig. 34.— Sinepuxent Bay, Maryland. Im. ? 

 Type of B. tectirostns (Cope). Fig. 35.— Cape Cod, Mass. Im. No. 16039 U. S. N. M. Fig. 36.— Cape Cod, 

 Mass. Im. No. 16045 U. S. N. M. 



PECTORAL LIMBS. 



The figures of the scapula of B. 2)^'ysalus published by Malm (65, pi. 3, fig. 

 5) and Fischer (44, pi. 2, fig. 4) show the superior, or spinal, border quite evenly 

 convex and the acromion low. These are probably incorrect, as Menge's photo- 



