VISCERA OF AN OKAPI. 



201 



The Tonsils (text-figs. 1, 4, 6). 



« 



The tonsillar fossa of the Okapi lies in the usual position (text- 

 fig. 15, t.f.), between the anterior and posterior pillars of the fauces 

 somewhat in advance of the hinder free margin of the palate. It 

 is a simple oval pit, with its fundus subdivided into two or more 

 subsidiary recesses. The fossa and the area surrounding it are 

 covered externally by a nodulated mass of tonsillar tissue, which 

 is encapsulated by a thin longitudinal sheet of muscle derived 

 from the muscles of the palate. 



The tonsils are thus of quite a usual Rumina.nt type, and very 

 .similar to those of the Giraffe. It is interesting, however, to 

 note that in many Ruminants the single fossa is replaced by a 

 row of separate incisions, which no doubt represent the subsidiary 

 recesses in the fundus of the common fossa of the Okapi. 



The Palate. 



In 1915 the Royal College of Surgeons purchased the roughly 

 prepared skeleton of a young male Okapi collected by Dr. Christy, 

 in which the soft tissues covering the hard palate had not been 

 removed. They are shown in the accompanying photograph 

 (text-fig. 17). 



In front of the molar region the palate is extremely narrow, 

 and throughout this region is traversed by a series of about 15 

 major palatal ridges. The anterior three or four are weak and 

 do not extend across the entire breadth of the palate ; they 

 are succeeded by some twelve or so more complete ridges bowed 

 forward in the centre and with their free papillate edges directed 

 backwards. In the middle line these ridges are interrupted, the 

 right half of each being situated in the majority of cases slightly 

 posterior to the left. Behind the level of the anterior molar 

 teeth, the palatal ridges become less and less pronounced and 

 more nearly transverse in direction and gradually fade away, 

 leaving the greater part of the intermolar area of the palate 

 quite smooth. 



Between the major palatal ridges are series of papilla? arranged 

 transversely, forming minor ridges. 



As in the Giraffe, there is no papilla incisiva, but at the 

 extreme anterior end of the palate, in front of the palatal ridges, 

 are two little longitudinal slits — the openings of the naso-palatine 

 canals. 



The soft palate terminates posteriorly in a simple curved 

 border, without any indication of a uvula. Its lateral parts are 

 prolonged, as the posterior pillars of the fauces, and become con- 

 fluent upon the dorsal wall of the pharynx, forming, as in the 

 majority of quadrupeds, a complete circular lip (arcus palato- 



Proc. Zool. Soc— 1917, No. XIV. 14 



