142 THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 
16045 from Cape Cod, Mass. (See pl. 7, fig. 4.) The Cayeux specimen, cited by 
Fischer as young, appears to be exceptional in having the anterior border entire, 
with a vacuity below it, and the stem and wings scarcely differentiated. A close 
approximation to the normal form of the immature sternum is perpetuated in the 
adult in Malm’s Finmark specimen, and Sars’s Christiania Museum specimen. The 
latter leads to the more extraordinary adult form exhibited by the Groix Id., Albany 
(N. Y.) museum, Rochester (N. Y.) museum, and Langrune specimens, in which 
the anterior emargination is generally pronounced and the wings long and pointed. 
A quite different adult form is shown in the Vlieland Id., Herault, Borselaer 
(Schelde R.), Bayonne, and Cambridge (Mass.) museum specimens, in which the 
anterior border is convex, forming a fourth projection and converting the trefoil 
into a quatrefoil. This is carried 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 margin 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 aud Cambridge (Mass.) museum specimens. 
In all these variations the American specimens run parallel with the European 
ones. 
FIG. 33. 
FIG, 34. Fic. 36. 
SCAPULA OF BALATNOPTERA PHYSALUS (L.). AMERICAN AND EUROPEAN. 
Fic. 33.—LoroTen Ips., Norway. Jr. (FRoM Sars.) FIG. 34.—SINEPUXENT BAY, MARYLAND. IM. ¢ 
Type oF B. tectirostris (COPE). Fic. 35.—CAPE Cop, Mass. Im. No. 16039 U.S. N.M. Fic. 36.—CAPE Cop, 
Mass. Im. No. 16045 U. S. N. M. 
PECTORAL LIMBS. 
The figures of the scapula of 5. physalus published by Malm (65, pl. 3, fig. 
5) and Fischer (44, pl. 2, fig. 4) show the superior, or spinal, border quite evenly 
convex and the acromion low. These are probably incorrect, as Menge’s photo- 
