SUXUAL SELECTION 683 



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 acci- 

 dents 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 de- 

 veloped in the males during youth.' 



Odor. — With some animals, as with the notorious skunk 

 of America, the overwhelming odor which they emit appears 

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

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

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

 beasts of prey, that the odor is protective; nevertheless, the 

 glands become enlarged in the males during the breeding 

 season. In many other quadrupeds the glands are of the 

 same size in both sexes," but their uses are not known. In 

 other species the glands are confined to the males, or are 

 more developed than in the females; and they almost al- 

 ways become more active during the rutting season. At 

 this period the glands on the sides of the face of the male 

 elephant enlarge, and emit a secretion having a strong 

 musky odor. The males, and rarely the females, of many 

 kinds of bats have glands and protrudable sacs situated in 

 various parts ; and it is believed that these are odoriferous. 



The rank effluvium of the male goat is well known, and 

 that of certain male deer is wonderfully strong and persis- 

 tent. On the banks of the Plata I perceived the air tainted 



8 On the sea-elephact, 8ee an article Toy Lesson, in "Diet. Class. Hist. 

 Nat.," torn. xiii. p. 418. For the Qystophora or Stemmatopus, see Dr. Dekay, 

 "Annala of Lyceum of Nat. Hist New York," vol. i., 1824, p. 94. Pennant 

 has also collected information from the sealers on this animaL The fullest 

 account is given by Mr. Brown, in "Proe. Zoolog. Soe.," 1868, p. 436. 



» As with the casloreum of the beaver, see Mr. L. H. Morgan's most 

 interesting work, "The American Beaver," 1868, p. 300. Pallas ("Spia 

 Zoolog.," fasc. viiL, 1779, p. 23) has well discussed the odoriferous glands of 

 mammals. Owen ("Anat. of Vertebrates," voL iii. p. 634) also gives an ac- 

 count of these glands, including those of the elephant, and (p. 763) those 

 of shrew-mice. On Bats, Mr. Dobson in "Proc. Zoolog. Soc.," 1873, p. 241. 



