Mr A. H. Guerin on the Rock-Nose Jriiale. 269 



believe them distinct from each other ; although the whalers 

 in general seem to think that it is merely a difference of age 

 that causes this difference in their external characters. This, 

 however, appears to me very improbable. If we take a glance 

 at zoology in general, we find that animals of about the 

 same age are about the same size, when under similar cir- 

 cumstances. I would, therefore, be inclined to believe that 

 two whales of the same species, of the same length of whale- 

 bone, would be of about the same age, and would present 

 nearly the same external characters ; but when we find a 

 constant and considerable difference both in habits and 

 form, we may, with I'eason, infer that the two individuals 

 are marked varieties at least, if not different species. Be- 

 sides, we generally find, among animals, that those that are 

 fit for reproduction, or have already given birth to one or 

 two individuals, have attained the regular proportions and 

 the instincts belonging to that particular species. Now, as 

 cubs or suckers are as often found among the Rock-noses as 

 among the Middle ice whale, the former must have attained 

 the age of maturity ; as we cannot suppose that the Green- 

 land whale can be an exception to the general rule. I can- 

 not believe, therefore, that a number of these animals, after 

 they have arrived at maturity, should still retain a difference 

 in shape and habits, confining themselves to the bays and in- 

 lets ; whilst the other portion, at the same period of life, 

 changing its instinct and shape, leaves the shore and goes to 

 roam at 30 or 40 leagues from the coast, and that under the 

 same latitude, the same climate, and under similar external 

 circumstances. I therefore conclude that the Rock-nose is 

 a distinct variety, if not a distinct species. There is no 

 doubt that the Middle ice whale is the true Balasna Mystice- 

 tus ; but whether or not the Rock-nose is the same species 

 as the Mysticetus of tlie South Sea, is a question I am not 

 able to decide. 



