4 DR. C. F. SON'NTAG O.V THE AXATOMY 



and hemispherical, and others may possess a central boss (text- 

 fig. 2 A, I, m, n). All the conical papillae have their points 

 directed backwards. The lateral borders are full and rounded 

 (text-fig. 1 D, a) ; they are beset with both conical and fungi- 

 form papillae, and the lateral organs are situated at their 

 posterior extremities (text-fig. 1 B, g). 



Mesial Sulci. — Mesial sulci may be present on the dorsal and 

 inferior surfaces. In my fresh specimen (text-fig. 1 A) the 

 median dorsal sulcus extends from the apical notch to a point 

 4 mm. in front of the antero-median vallate papilla. It is 

 irregular and invaded by both conical and fungiform papilla? ; 

 posteriorly it is deep and lodges fungiform papillae alone. On 

 the base of the tongue the median row of vallate papillae is 

 situated on a depressed band of mucosa which is bounded by 

 large papillae and lymphoid nodules. 



In my second specimen there is, instead of a median sulcus, a 

 row of prominent fungiform papillae, and the only representative 

 of the fissure is a small pit, lodging a fungiform papilla, lying 

 immediately in front of the antero-median vallate papilla. 



In my third specimen (No. J. 359.1, Mus. R.C.S.) there is 

 neither a median sulcus nor a median row of fungiform papillae, 

 but there is a pit in front of the antero-median vallate papilla. 



The small pit described above must not be mistaken for the 

 foramen cceciom of Morgagni which is absent in the Chimpanzee. 

 The median ventral sulcus will be described later. 

 Transverse ridges and. stdci are absent. 



The Papillae. 



Papillae are present on the entire dorsum, apex, lateral borders, 

 and a bounding zone on the inferior surface. This general distri- 

 bution is so common among the Anthropoids that it can be 

 regarded as the rule. The only exceptions are the Orang-Outan 

 and the Siamang Gibbon, which have areas on the base which are 

 devoid of papillae. I am unable to say whether these smooth 

 areas exist in all Siamangs, but they are not present in all 

 Orangs. 



The Circumvallate Papillce (text-fig. IB, c & d). 



The vallate papillae vary in number and arrangement in dif- 

 ferent individuals, but the relation between the species of 

 Chimpanzee and the papillary pattern has not been stated by 

 authors. The following types have been described : — 



T-form: Flower (28); Dwight (123); Symington (202); 

 Huxley and Hunter. 



Y-form: Gratiolet and Alix (131) ; Bischoff (7) ; Miinch [1], 



V-form: Cavanna(109) ; Ehlers (23). 



Cruciate form : Mayer (162). 



Linear type: Humphry (142). 



The numbers of vallate papillae vary from three, as recorded 

 by Wyinan (215), to fifteen mentioned by Humphry (142). 



