THE GREAT ANTEATER. 129 
genio- and sterno-glossi, the fifth pair of nerves (Pl. XXXIX. fig. 2, 0), which have 
arched almost transversely beneath the lower part of the gular pouch, converge to 
penetrate the tongue at the base of the freenum. 
Epthyoglossi.—Beneath the insertions of the geniohyoidei (PI. XXXVIIL fig. 1,1, ]), a 
pair of more slender muscles (tb. k, k) come off from the median ends of the epihyals. 
These muscles, after a brief course, expand into a thin layer, resolve themselves into 
separate fasciculi, and combine an inch in advance of their origin to form a layer about 
eight lines in breadth below the middle line of the postlingual part of the mouth ; which 
layer (k) slightly diminishes in size as it approaches the commissure of the sterno- 
glossi (A), and, with them, penetrates the back part of the frenum lingue. The antero- 
posterior diameter of the base of the tongue, where it rises freely from the buccal 
membrane (Pl. XX XVIII. fig. 2, 0, p,7), is three and a half inches. The convergence 
of the sterno- and genio-glossi, with the connecting frnal fold, forms a triangle, from 
the apex of which the tongue, b, assumes its vermiform shape, gradually diminishing 
from a breadth of eight lines to the obtuse apex which is one line in breadth, the length 
of this free part of the tongue being eighteen inches. 
The tongue is covered by a smooth shining epithelium, which begins to present a 
softer, more vascular or mucous character fourteen inches from the apex ; but the only 
papillee anywhere present are two fossulate ones, ‘papillz vallate’ (Pl. XX XIX. fig. 3, f), 
forming a pair, two lines apart, situated on the dorsum of the tongue about two inches 
in advance of the termination of the frenum. A linear groove, commencing two inches 
from the base of the tongue, extends along the dorsum to within four inches of the apex. 
The muscular substance of the free part of the tongue is formed by the lingual por- 
tions of the sternoglossi, by the genioglossus, and by the proper ‘ linguales’ muscles. 
The buccal membrane (Pl. XX XIX. fig. 3, p, q) is smooth, perforated at its lateral and 
inferior parts, and also superiorly beyond the bony palate, by innumerable very minute 
orifices, from a quarter of a line to one line apart, by which the secretion of the thin 
glandular stratum before described enters the mouth. 
Four inches in advance of the angle of the jaw, near the lower border of the ramus, 
a longitudinal ridge or low fold of the buccal membrane begins to rise, increasing in 
depth and assuming a callous hardness as it extends forwards and upwards: this ridge 
(Pl. XXXIX. fig. 3, r) is about two lines in breadth, and bends down so as to leave a 
groove between it and the lower membrane of the mouth. It is possible that the 
Termites may be crushed by the action of the tongue against these two callous ridges, 
which seem to occupy the place of teeth on each side the mouth. 
The cavity of the mouth quickly expands as it passes backward and acquires its 
greatest breadth opposite the base of the skull and of the tongue (7b. fig. 3, p, q), having 
there a diameter of from four to five inches. The thin membrane, over which the 
diverging fasciculi of the sternoglossi and hyoglossi spread, is capable of considerable 
dilatation, and may serve, therefore, as a temporary receptacle for the Termites, where 
VOL. [V.—PART IV. U 
