576 



THE AMERICAN NATURALIST 



[\'oL. XL 



each side of the h)wer jaw is a low narrow ridoe whicli is marked 

 off by a slight furrow from the rest of the chin. This ridoe as well 

 as a broad adjacent strip of the chin is thickly set with short fine 

 bristles. The remain(l(>r of the surface of the chin bears coarser 

 and more scattered l)ri>tle> rach of which springs from a small 

 dark pit, just as in the case of the fold at the edge of the mouth 

 near the palatal process. 



In reviewing the literature on this subject we will first consider 

 the account given by Riippel. Contrary to our observations, he 

 states that the long median furrow of the snout is bifurcate ven- 

 trally so that its form is that of an inverted Y. By this bifurcation, 

 this portion of the snout is divided into three parts, the two upper 

 of which belong with the nose while the small lower triangular 

 part forms the upper lips proper, directed toward the inner sur- 

 face of the mouth. It is of course obvious that the long vertical 

 furrow spoken of by Ruppel is identical with that described by us. 

 The bifurcation which, as our description shows, has nothing 

 particular to do with the median furrow, is the bow-shaped depres- 

 sion formed by the snout proper and the palatal process. The 

 small three-cornered portion below is the palatal process, which 

 of course has no connection whatever with the lips. Rapp speaks 

 in only a general way of the Sirenian snout. He states that the 

 upper jaw ends anteriorly in the form of a flat blunt disc richly 

 provided with nerves, that perhaps functions as an organ of taste; 

 and further, that in the case of the dugong particularly, the "lips" 

 are very thick and they a.> well as the corners of the mouth toward 

 the inner side of the cheeks bear thick stul)by bri.stles. Krauss 

 makes no mention of the median furrow of the snout but describes 

 the side folds which Ruppel omits. Both authors give detailed 

 accounts of the (Hstribution of hair on the snout. Krauss, how- 

 e\cr, ( orrc( tl\ dt'scribes the palatal process and the fold at the 

 educ ot file lower jaw. Rn^hm and Finsch make mention of the 

 ''-^ id.M) Owen who considered its peculiar 

 forn. to lie ..>[.,.. iall> ndapKMl for the takintr of food. Turner 

 gaxe an extcndci ar,o,mt of tlie hea.l of an adult female dugoni,' 



of his specimen with (h-v ^;,h nnnt have been verv Inn- for it is 

 greatly shrunken and out of shape. In conse(,uence, the descrip- 



