MORPHOLOGY OF DUGONG 



not continued into the posterior fold, which iiisttad conu-. from 

 the lateral portions of the middle area ( Fi^>. ■!. . 'rurner 

 describes the <jreatly shrunken palatal ])r()cess in his >])r( inirn as 



of its being cut by the uie-lian furrow, is misleadin^ly callt'il "lat- 

 eral lips," so that in considering the homologies of the parts men- 

 tioned, it is necessary to take into consideration the probable 

 shrinkage that they have undergone. 



Of particular interest, naturally, are the eml)ryological condi- 

 tions as pictured in Kukenthal's dcetclies of a freshly preserved 

 fetus. These sketches are much more satisfactory tiian the Hirures 

 of the fetus given by Turner. In all the embryos the deep median 

 furrow of the middle area is apparent. In his fourth stage. Kiiken- 

 thal was able to make out a shallowing of this furrow in the region 

 of the lip. From the fact that this portion of the furrow was lack- 

 ing in Turner's figure of the adult, Kiikenthal concluded that a 

 fusion had here taken place between two originally separate por- 

 tions in such a way that the two lateral parts of the upper lip had 

 become united medially. In further sn})port of this view, he cited 

 Ruppel's figure, which as we have shown above is to be otherwise 

 interpreted and is thus unavailable as evidence on this point. In 

 our specimen the median furrow extended to the gum, and, since 

 Turner's figure is untrustworthy, it can hardly l)e held that the 

 two portions of the middle area are united at the posterior part of 

 the furrow. At the same time we do not wish to coiuc^t Kiiken- 

 thal's conclusion that the snout of the dugonu-. winch in th<' adult 

 is rather simple, has beconu' like that of the manatee through a 

 division into a median area and two lateral areas and that thu^ the 

 manatee's snout is phvloucneticallv the older. For with thi. con- 

 clusion we are in heart^^ .vnipathy. d'hi> third median portion 

 is to be found at the upper end of the m.-dian furrow a> indicated 



