OF THE TONGUES OF THE MAMMALIA. 23 



and inferior surfaces into continuity. The rest of the inferior 

 surface is bluish black in colour. 



Apex. — -The obtuse apex has a fine central notch. It bears fine 

 conical papillae on the dorsum and lateral borders, and both 

 conical and fungiform papillae on the inferior surface. The 

 conical papillse are of the cylindrical and filifoi-m types, and the 

 latter have their points directed backwards. The numbers of 

 points differ greatly. 



Median sulci. — Median longitudinal sulci are present on both 

 dorsum and inferior surfaces. The median dorsal sulcus runs 

 back from the apex for a distance of 1*4 cm. The median 

 inferior sulcus begins at a point "5 cm. posterior to the apex for 

 1*5 cm,, becoming wider as it goes, till it opens into a triangular 

 area to which the frenum is attached. It is shut off from the 

 apex by the papillary border. 



Lateral borders. — The lateral borders have fungiform and 

 conical papillae. The latter are both cylindrical and filiform 

 with their points directed backwards. 



The inferior surface. — The inferior surface is surrounded by a 

 papillary border which is rough to the touch ; it varies in width 

 from "2 cm, at the apex to '5 cm. at the lateral organs, so it 

 becomes wider when it is traced backwards. It bears both fungi- 

 form and conical papillae. The former are arranged in two rows, 

 of which the inner one consists of closely-set elements, but the 

 outer papillae are more discrete. There is, however, no disposi- 

 tion according to size, for both rows have different sizes of 

 members. The conical papillae are cylindrical and filiform with 

 their points directed backwards. 



Internal to the papillary border the mucous membrane is 

 smooth and, with the exception of the mesial sulcus, f uriowless. 



Pliccefmbriatte, lytta, foramen ccecum, and the Anneal gland of 

 Nuhn are absent. 



The Papillae. 



Papillae cover the entire dorsum, the apex, lateral bordei'S, and 

 a bounding zone of the inferior surface. 



The Circumivallate Papillce. 



There are three vallate papillae arranged in the form of a 

 triangle whose apex is in the mid-line posteriorly, and the vertical 

 angle included is obtuse. The lateral papillae, which are simple, 

 are '7 cm, distant from the compound apical papilla and 1-3 cm, 

 from one another. 



The apical papilla is very prominent, is oval in shape with the 

 long axis antero-posterior, and measures '6 cm. by -3 cm. Its 

 fossa is narrow and irregular, and lodges two elements (text- 

 figs. 7 & 9, 17). These have smooth glistening bodies, and the 

 anterior one has a small central depression. The entire series of 

 elements is dumb-bell-shaped and the vallum sends small lobules 



