CETACEA. 35 



Ray calls these Baltena tripennis, thus separating them from 

 those which have no dorsal fin ; but Polach misunderstood him, 

 and says they have three fins on their back. 



Sibbald (Phalcenologia Nova, 1692) figures two specimens of this 

 genus caught on the coast of Scotland. Ray (Hist. Piscium, 1 7) 

 notices these specimens ; and Brisson and Linnaeus have regarded 

 them as separate species. Linnaeus designated the one with the 

 skin under the throat dilated, Balcena musculus, and the other, 

 with this part contracted and flat, B. Boops. Now, as I proved 

 by the examination of the specimen we have in the British Mu- 

 seum, when alive, and as M. Ravin observes (Ann. Sci. Nat. v. 

 275), this skin is very dilatable, so that these characters appear to 

 depend on the manner in which the specimen might he when 

 drawn, and the quantity of gas which might have been produced 

 by the decomposition of the interior. Ray, and after him Bris- 

 son and Linnaeus, established a third species, B. Physalus (S. N. 

 i. 186), on the Fin-fish of Martens (Spitz. 125. t. Q. f. c), copied 

 E. M. t. 2. f. 2, which well represents this genus ; yet as there 

 are no folds on the belly in the figure, it has been regarded by 

 most authors as distinct from the B. rostrata of Miiller and 

 Hunter, and the other species of Sibbald ; but the name used by 

 Martens being the one now given by the Greenland whalers to these 

 whales, I think at once shows that it properly belongs to this genus : 

 and Martens neither mentions the colour, nor says a word about the 

 belly. Scoresby, who calls the Fin-fish B. gibbar, after Bonnaterre, 

 says from report that the " skin is smooth, except about the sides of 

 the thorax, where longitudinal rugae or sulci occur," which at least 

 must be a Balcenoptera. Lacepede formed the Fin-fish of Mar- 

 tens, the Hunch-back and Scrag Whale of Dudley, into a section, 

 which he calls Rorqual a ventre lisse. The Hunch-back has a 

 "reeved" or plaited belly, and the Scrag Whale is shaped like, 

 and doubtless is, a true Balaena ; yet these species are kept to- 

 gether as a subgenus in Fischer and other modern systematic 

 works: and Dr. Fleming has made Lacepede's section into a 

 genus, under the name of Phy satis. 



The examination of the skeleton has shown that there are 

 several species found in the North Sea characterized by the bones 

 of the neck and by the external colour ; and I think there is little 

 doubt that, when we have had an opportunity of comparing the 

 skeletons of the Finner Whales found in the other seas, espe- 

 cially of those in the Southern hemisphere, we shall find that they 

 are perfectly distinct from those here described. 



The following synonyma of Northern species of Finners appear 

 to belong to this genus, but it is not possible to apply them with 

 any certainty to the species here described : 



