Cetacea. 1 533 



Lastly, the third species, which seems to be the commonest, has the 

 baleen bluish gray posteriorly, whitish anteriorly ; never any terminal 

 tuft on the upper jaw ; the pectoral fins having only an external white 

 spot in the young ; the back black or blackish ; the thoracic folds 

 whitish in the young, having the intermediate canaliculations black- 

 ish in the older ones ; the pectoral fins placed before the anterior 

 third of the body ; the upper lip immaculate, and the vertebrae about 

 sixty ? in number.* 



It might be imagined that the differences I have just mentioned are 

 simply the result of age or accident ; here are my answers to some 

 objections which might be made in opposition to my statements. If 

 the colour of the baleen be entirely caused by age, why is it that, 

 amongst others, the specimen stranded at Deptford in 1843,f and 

 which had only attained the length of fourteen feet, had it dark, J while 

 the one which I have studied, and which was nearly twice as large, had 

 its whalebone entirely white, which colour, to agree with the gene- 

 rally received notion, ought to have changed to black again, before the 

 animal had attained its full size, as the very large Baleinopterae (an- 

 swering to my first species) always have it black ? I believe this trans- 

 mutation to be very improbable, for amongst all the whales of this 

 description observed until this present period, and the number of 

 them is very considerable, no intermediate state between the dark and 

 the white has been described, and in my third species the two colours 

 are very distinct from one another. 



Perhaps it will be said, that the colour of the baleen is quite acci- 

 dental, and is of no importance as a specific character. In answer to 

 this supposition I shall only ask, why may it not be regarded as a 

 character which, united to others, may be successfully made use of to 

 separate closely allied species ? Do not the shrew-mice and Roden- 

 tia present good characters, derived from the colour of the teeth ? 

 Has the common whale ever been found with white baleen ? What 

 causes could effect such considerable differences in parts which cor- 

 respond to the teeth of other animals, &c. ? 



It is only when all these questions have been answered, and that 

 the generation and growth of the Cetacea has been carefully followed, 



* To this species, the whales described by Ravin, Schlegel, Rudolphi, &c. may be 

 referred. 



t See 'Zoologist,' vol. i. p. 33. 



% I owe the knowledge of this fact to the kindness of Mr. Gray. 



