ANATOMY OF MEGAPTERA LONGIMANA. 7 



diagram l the dorsal fin is not very like this one, stands up more, 

 and the point and both margins are different. In the small 

 figure given by Eschricht (p. 152, fig. 48), the notch is much 

 less marked than in this one. As seen in my figure, the 

 anterior slope is a little concave on the basement, and becomes 

 convex on the fin proper. No exact spot could be fixed on 

 here for the commencement of the fin proper as distinguished 

 from the basement, but the level of the notch behind determines 

 that to the eye. The point is some way behind the top, with a 

 fall of about 1 inch. The posterior border below the point is 

 convex down to the bottom of the notch. This, with the gentle 

 concavity of the posterior slope of the basement, renders the 

 notch pretty sharp, more so than in the higher and more 

 recurved fin of B. musculus. 2 



As to situation, the distance from the cleft of the tail to the 

 notch of the dorsal fin was 12 feet 4 inches of the 40 feet. In 

 my 64-feet-long B. musculus the distance was 15 feet 8 inches 

 (height of fin 15 inches, length at base 24 to 26 inches). This 

 would place the dorsal fin further forwards in Megaptera than 

 in B. musculus. 



7. TAIL-FIN. The form of the tail-fin is shown in fig. 3, Its 

 greatest antero-posterior breadth was 3 feet, only 3J inches 

 more than the breadth of the pectoral fin ; its total width less 

 than the length of the pectoral fin by 8 inches. The statement 

 of the depth of the median cleft, commonly said to be deep, will 

 depend on where the measurement is taken. From between 

 the neighbouring convexities, about 7 inches out, the depth is 

 3 J inches ; from between the first prominent serrations, about 



1 Abhand. konig. Acad. der Wissenschaften, Berlin, 1829, Taf. v. fig. 1. 



2 I have noted these points particularly on account of the question of the origin 

 of the name " Humpback " for this species. " Les megapteres ont une bosse sur 

 le dos a la place d'une nageoire" "une veritable bosse dependante de la peau," 

 says the eminent cetologist P. J. van Beneden. There was nothing in the 

 appearance of the back of this Megaptera to suggest to us the appropriateness of 

 the name Humpback. That, however, will depend partly on the idea one 

 associates with the word humpbacked. The name may have arisen rather from 

 the rounded back Megaptera shows above water, as long ago suggested and 

 figured by Eschricht (Untersuchungen iiber die Nordischen WalltMere, p. 152, 

 fig. 48) : " Der Name Humpback scheint iibrigens nicht nur von der Riicken- 

 flosse, sondern eben so wohl von dieser Kriimmung des Riickens beim Unter- 

 tauchen." The term, though rather misleading as to the true form, is a con- 

 venient one to the whale-fishers. 



