126 



THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 



Fig. I. 



Fig. 5. 



Fig. 3. 



Fig. 2. 



Fig. 6. 



Fig. 4. Fig- ^■ 



DORSAL FIN OF BAL^NOPTERA PHYSALVtS (L.). AMERIC.4.N AND EUROPEAN. 



Fig. I.— Snook's Arm, Newfoundland. Ad. S . No. 24. Fig. 2.— Snook's Arm, Newfoundland. Ad. 

 ?. No. 25. Fig. 3. — Snook's Arm, Newfoundland. Ad. 2 . No. 23. Fig. 4.— Gloucester, Mass., Im. S. 

 (Fko.m DwiGHT.) Fig. 5.— Finmark, Norway. Ad. (From Malm.) Fig. 6.— Borselaer, Netherlands. Ad. 

 i. (From Van Beneden.) Fig. 7— Lofoten Ids., Norway. Jr.,! (From Sars.) 



PECTORAL FIN. 



The shape of the i)ect()i'al fin in the European B. lyliyaaluH, accoi-ding to Sars 

 is "narrowly lanceolate, with the posterior angle often but little distinct." This is 

 true of the Newfoundland Finbacks. Tlie anterior border is much straighter than 

 in the Sulphurbottoms, and the distal half of the posterior margin, which is quite 

 strono-ly concave in the latter, is straight in the Finback. These straight contours 

 and the small size give the pectoral of the Finback a tiiangular appearance, quite 

 different from that of the Sulphurbottom, as will be seen by comparing pi. 11, 

 fifi'S. 1, 2, and 4, and |)1. 21. The shape of the pectoral of B. physalus is not 

 as well shown in Sars's figure {79, pi. 2) as in Delage's photographs {33). In the 

 former the anterior margin is too much curved, especially in the proximal half, and 

 the posterior margin is too convex near the axilla. Much better are Sars's litho- 

 graphic figures of his Lofoten Ids. specimen {77, pi. 2, figs. 3 and 4), in which the 

 triangular shape of the pectorals is admirably portrayed, though perhaps a little 

 exaggerated. 



There is some variation in tlie relative length and width of the pectoral, as 

 will be seen by consulting the table on p. 117, but it is not sufficient in any case to 

 destroy the characteristic shape of the fin. 



In some Newfoundland specimens the contours are much more regular than 

 in others, and in No. 17 there was a deep emargination at the tip anteriorly, due 

 possibly to injury. In No. 3 the tip of the left pectoral was blunt and ii-regular, 

 due to injuries. 



