528 The Descent of Man. Part U. 



and enlarged througli the inherited effects of long-continued 

 use without any particular good being thus gained — I will not 

 pretend to say ; but the former Tiew, at least in the case of the 

 Hylohates agilis, seems the most probable. 



I may here mention two very curious sexual peculiarities 

 occurring in seals, because they have been supposed by some 

 writers to affect the voice. The nose of the male sea-elephant 

 (^Macrorhinus prohoscideus) becomes greatly elongated during the 

 breeding-season, and can then be erected. In this state it is 

 sometimes a foot in length. The female is not thus provided at 

 any period of life. The male makes a wild, hoarse, gurgling 

 noise, which is audible at a great distance and is believed to be 

 strengthened by the proboscis ; the voice of the female being 

 different. Lesson compares the erection of the proboscis, with 

 the swelling of the wattles of male galhnaceous birds whilst 

 courting the females. In another allied kind of seal, the bladder- 

 nose (Cystophora cristata), the head is covered by a great hood 

 or bladder. This is supported by the septum of the nose, which 

 is produced far backwards and rises into an internal crest seven 

 inches in height. The hood is clothed with short hair, and is 

 muscular; it can be inflated until it more than equals the 

 whole head in size ! The males when rutting, fight furiously on 

 the ice, and their roaring " is said to be sometimes so loud as to 

 " be heard four miles off.' When attacked they likewise roar or 

 bellow; and whenever irritated the bladder is inflated and 

 quivers. Some naturalists believe that the voice is thus 

 strengthened, but various other uses have been assigned to 

 this extraordinary structure. Mr. E. Brown thinks that it 

 serves as a protection against accidents of all kinds ; but this is 

 not probable, for, as I am assured by Mr. Lament who killed 

 600 of these animals, the hood is rudimentary in the females, 

 and it is not developed in the males during youth.* 



Odour. — With some animals, as with the notorious skunk of 

 America, the overwhelming odour which they emit appears to 

 serve exclusively as a defence. With shrew-mice (Sorex) both 

 sexes possess abdominal scent-glands, and there can be httle 

 doubt, from the rejection of their bodies by birds and beasts of 

 prey, that the odour is protective; nevertheless, the glands 

 become enlarged in the males dui'ing the breeding-season. In 



' CK; the sea-elephant, see an 1824, p. 94. Pennant has also 



article by Lesson, in 'Diet. Class. collected information from the 



Hist, l^at.' torn. xiii. p. 418. For sealers on this animal. The fullest 



the CystophDra or Stemmatopus, account is given by Mr. Brown, U 



sw Dr. Delcay, ' Annals of Lyceum ' Proc. Zoolog. Soc' 1868, p 435, 

 af Kat. Hist. New York,' vol. i. 



