THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 



227 



Jiofc exactly the same, having a much straighter posterior mai-giii and a knob-like 

 tip jouied to it ill a manner which makes the figure appear diacrramraatic The 

 dorsal on the fcetus itself {37, pi. 3, fig. 1) is short, erect, and lias a'slightly concave 



Fig. 70. 



Fio. 71. 



Fig. 68. 



Fig. 6y. 



Fig. 72. 



ilEGAPTERA NODOSA (bONNATEKBe). PECTORAL AND DORSAL FINS. 



Fig. 6S. — Tay River, Scotland. Bones of pectoral fin. (From Struthers.) Fig. 6g. — Provincetown, 

 Mass. Exterior of pectoral fin. (From a photo.) Fig. 70. — Greenland. Dorsal fin of a f<etus. (From 

 EscHRicHT.) Fig. 71. — The same, enlarged. Fig. 72. — Tay River, Scotland. Dorsal fin. (From Struthers.) 



posterior margin like adult Newfoundland specimens, but of course more unde- 

 veloped. (See text figs. 70, 71.) 



Hoi boll describes the dorsal of the adult Keporhah (37, 76) as "low, broad on 

 the side, cut o£E almost straight toward the tail ; in general, shaped like a broad 

 lump of fat with a knob." Fabriciiis describes it as "compressed, with a broader 

 base, the apex a little acute, in front sloping upward (sursum repandd), behind 

 almost perpendicular," but adds " some are obtained, however, which have the apex 

 equally curved, in some longer, in others shorter." Motzfeldt's description of the 

 dorsal fin is as follows (37, 198) : "The dorsal fin of the Keporhak has as a very 

 salient character a protuberance or knob on the anterior (upper) margin." 



Brandt describes the dorsal fin of the Humpback as having "a convex upper 

 border, gradually rising, ending at its highest point behind and above in an obtuse 

 backward-curved tip, below which is a considerable emargiiiation, . . . and 

 then gradually merging into a ridge running forward from the tail." 



Sars's figure of a Fiumark Humpback {80, pi. 2) shows the dorsal fin strongly 

 concave posteriorly. His description is as follows : 



"As in some species of the genus BalcenopUra, it is compressed like a scythe, 

 with a rather thick and strongly convex anterior bordei', and a thin, sharp, and 



