KUHGL. SV. .yBT. AKADEMIENS HANDLINGAR. BAND 58* N:0 2. 101 



The hairs on the lower lip are in a corresponding manner directed towards its upper 

 margin, wher^ the hairy covering ceases just as abruptly as on the upper lip. In addition 

 to the normal fur ,of these p^rts there are to be seen a greet number of long black bristles 

 with undoubtedly sensory lunction, These attain their strongest development on the 

 chin, and lower hp, but they are numerous on the upper lip as well (conf. the fig, 9). 



The nostrils are partly hairy within at their border?. 



With regard to colour and pattern this animal has been so fully described especially 

 by Fbaipont in his great monograph'^ that there is no need to comment further upon 

 this. The dorsal mane, or crest extends in these young animals from the nape to the 

 l^ail^ but the hairs, of which i|; is composed, are considerably coarser on the fore-quarters 

 than above the sacral region. 



The structure of the upper lip and snput region of these Okapi calves, as describ- 

 ed above, is very interesting at it illustrates in a very clear manner a stage of develop- 

 ment which is intermediate between the more primitive condition found in the CameZicte 

 with their divided upper lip on one hand, and the various stages of a more or less 

 developed muffle which among the Gavicornia reaches its culmen in the Bovinoe. The 

 mode of development is not difficult to understand. The cleft lip . of the Gamelidce repres- 

 eaits a primitive stage, which is repeated in the ontogeny of other Ruminantia. In the 

 adult stage of the latter, however, the lateral portions of the upper lip have joined 

 mesially in front and grown together. The above described vertical groove in the upper 

 lip of the Okapi calves represents the remnants of this seem, or line of coalescence.* 

 The inner side of the lip is, of course, lined with a continuation of the mucous covering 

 of the mouth cavity, while the outer surface is protected by the ordinary skin. When 

 in the foetal stage the lateral halves of the upper lips have grown forward so as to meet 

 each other mesially, and the concrescence begins, the line of junction may get a some- 

 what variable situation in relation to the different coverings of the inner and outer sur- 

 faces of the lip. If the line of junction is situated just where both tissues meet the 

 result will be that the whole anterior surface of the upper lip is covered with skin which 

 develops hair just as the skin elsewhere, and thus no naked rhinarium is formed as is 

 the case in the Giraffe, Reindeer, Muskox etc. If, however, the mucous lining of the 

 mouth hias grown forward so much that the junction of the lateral halves of the lip fall 

 inside the anterior limit of this mucous. tissue, the result will be something similar to the 

 condition described above in the Okapi calves, viz. a bare mucous strip along the line 

 of concrescence. As has been mentioned, this bare strip derived from, and forming a 

 femnant of the mucous lining of the mouth cavity is a little broader at its upper end, that 

 is just in the inner angle of the cleft between the lateral portions of the lip. It appears 

 thus as if the mucous cqvering of the inside had a stronger tendency to grow out jiist 

 there than along the edges below. If this has happened, and, accordingly, when the 

 cleft in the lip is closed, oiily a portion of mucous tissue has remained exposed at the 

 upper end of the. seem, the result will be a small naked rhinarium, isolated far from the 



1 Ann. du Musee du Congo. Zool., Ser. Ill, T. .1, Bruxelles 1907. 



^ A homologous, although somewhat different groove in the upper lip is, of course, also found among the 

 Sheep, several Antelopes etc. 



