THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIO. 227 
not exactly the same, having a much straighter posterior margin and a knob-like 
tip joined to it in a manner which makes the figure appear diagrammatic. The 
dorsal on the feetus itself (37, pl. 3, fig. 1) is short, erect, and has a slightly concave 
FIG. 71. 
ee ee 
FIG. 69. Fic, 72. 
MEGAPTERA NODOSA (BONNATERRE). PECTORAL AND DORSAL FINS. 
Fic. 68.—TAy River, SCOTLAND. BONES OF PECTORAL FIN. (FROM STRUTHERS.) FIG. 69.—PROVINCETOWN, 
MAss. EXTERIOR OF PECTORAL FIN. (FROM A PHOTO.) FIG, 70,—GREENLAND. DORSAL FIN OF A F@TUS. (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.) 
Holboll describes the dorsal of the adult Aeporkak (37, 76) as “low, broad on 
the side, cut off almost straight toward the tail; in general, shaped like a broad 
lump of fat with a knob.” Fabricius describes it as “compressed, with a broader 
base, the apex a little acute, in front sloping upward (swrswm repanda), 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 Aeporkak 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 emargination, . . . and 
then gradually merging into a ridge running forward from the tail.” 
Sars’s figure of a Finmark Humpback (80, pl. 2) shows the dorsal fin strongly 
concave posteriorly. His description is as follows : 
“ As in some species of the genus Balwnoptera, it is compressed like a scythe, 
with a rather thick and strongly convex anterior border, and a thin, sharp, and 
