MAMMALS 71 



they fight furiously on the ice. The only difference between 

 this and the preceding case is in the shape of the distension 

 produced, a difference easily accounted for on the supposition 

 that the walls of the nostrils were more easily distended 

 in an upward and outward direction than in the elephant 

 seal. 



Almost all that has been stated above concerning the 

 proboscis of the elephant seal applies to the bladder of the 

 bladder-nose. The bladder is only developed in the males 

 towards maturity ; the males inflate the head when enraged 

 and when fighting, and they have a very loud roar. But 

 whether the roar is connected with the inflation there is no 

 evidence to show. There are, however, rather more definite 

 statements about the value of the hood or bladder as a means 

 of defence, for E. Brown 1 states that it protects the animal 

 from any stunning blow on the nose, the most vulnerable 

 place in a seal, and, according to Carroll, 2 it even protects 

 the animal against shot. But this does not prove that the 

 bladder protects the seal when fighting, for they do not fight 

 against one another with clubs or guns, and it is not certain 

 that the nasal region is particularly exposed to the adversary's 

 teeth. Blows and wounds in combat, if usually received on 

 the snout, might form in part the irritation to which the 

 hypertrophy is due, and the snout might have been inflated 

 by the animal in order to better resist the teeth of its 

 adversary. If this were proved to be the case it would afford 

 some support to the selection theory. At present, however, 

 it is not certain that the hood or bladder serves as a defence 

 in the fights of rival males, while, whether selection occurs 

 or not, it is certain that the animal when enraged inflates its 

 snout by forcibly distending it with air. Whatever gave 

 rise to the habit of inflation, whether it was as a means of 



1 Proc. Zool. Soc, 1868, p. 437. 

 2 Allen, North American Pinnipeds, Washington, 1880, p, 741, 



