THE OAT AS A TTPB GF THE MAMMALS. 229 



Lemur macaco is coal-black, while the female is reddish 

 yellow. The sexes of monkeys differ much in coloration. 

 Certain male seals, bats, rats, and squirrels have brighter 

 colors than in the opposite sex. On the other hand, the 

 female Rhesus monkey is adorned with a brilliant red naked 

 ring around the tail; this is wanting in the male, which, 

 however, is larger, with larger canines, more bushy whisk- 

 ers and eyebrows; and Darwin states that in monkeys the 

 males usually differ from the females in ''the development 

 of the beard, whiskers, and mane." 



When the cat mews or caterwauls the sound is caused by 

 the air rushing but of the lungs through the upper part of 

 the windpipe, which is called the larynx. The larynx is 

 formed by a modification of the uppermost ring of the 

 windpipe, called the cricoid cartilage, to the anterior and 

 dorsal edges of which two arytenoid cartilages are attached, 

 while a V-shaped thyroid cartilage, open behind, is at- 

 tached to its side. The vocal cords, which are modified 

 folds of the mucous membrane lining the windpipe, are 

 stretched between the arytenoid and thyroid cartilages, the 

 slit between them being called the glottis, which is covered 

 by the epiglottis. Thus, in the cat the organs of voice are 

 situated almost solely at the upper end of the trachea or 

 windpipe. In the voiceless whales the vocal cords are not 

 developed. The male gorilla, which has an exceedingly 

 loud voice, as well as the adult male orang and the gibbon, 

 is provided with a laryngeal sac. In the howling monkey 

 of Brazil, the hyoid apparatus and larynx are remarkably 

 modified, the body of the former being changed into a large 

 bony drum or air-sac communicating with the larynx. The 

 vocal organs are a third larger in the males than in the 

 females. " The males begin the dreadful concert, in which 

 the females, with their less powerful voices, sometimes join, 

 and which is often continued during many hours" (Darwin). 

 They apparently howl, as birds sing, for the simple pleasure 

 of the thing. Apparently, the most musical mammal, man 



