594 
CONTRIBUTIONS TO ZOOLOGICAL ANATOMY. 
The Stylo-glossus longus is situated along the entire side of the 
tongue, and immediately beneath its investing membrane and the 
sublingual gland. It arises posteriorly from the external surface 
of the apex of the styloid process of the temporal bone, and, pass- 
ing along the external surface of the hyo-glossus, becomes inserted 
by its superior edge into the substance of the tongue as far as the 
tip. As it proceeds onwards in its insertion, the substance of the 
muscle becomes greater, and beyond the body of the tongue it 
forms, with its fellow of the opposite side, nearly the entire sub- 
stance of the tip or point. Externally and inferiorly it is covered 
by the mylo-hyoideus the duct of the submaxillary gland, the 
gustatory branch of the fifth pair of nerves, and the mucous mem- 
brane covering the side of the tongue ; and internally it lies on 
the hyo-glossus, and genio-hyo-glossus muscles. The action of 
both muscles is to retract the entire substance of the tongue within 
the mouth, as also to turn upwards and backwards its tip, so as to 
carry any food from the roof of the mouth and the buccal, or cheek 
pouches, backwards to the isthmus faucium ; and from their be- 
ing in conjunction with the genio-hyo-glossi muscles that protrude 
the tongue, the inferior or anterior aperture of the nostrils and the 
lips and whiskers are cleared of any adherent matter, and carried 
within the mouth. They are, therefore , those muscles of the tongue 
that collect the food for the lips. One of these muscles acting 
alone, will place the tongue in the corresponding check pouch ; 
and it may be observed that these muscles are the most important 
of the intrinsic muscles of the tongue, inasmuch as they form 
almost the entire substance of its moveable portion or tip, and they 
also are the most important agents that contribute towards the 
function of the tongue as an organ of prehension. 
The Stylo-glossus brevis is a small muscle, and placed deeper 
than the preceding, between the hyo-glossus and the genio-hyo- 
glossus. It arises from the apex of the styloid appendage of the 
temporal bone and the point of the anterior cornu of the os hyoides, 
where its fibres join with those of the convex edge of the anterior 
chondro-hyoideus; and passing forwards into the centre of the tongue, 
it becomes inserted, partly with the stylo-glossus longus, and partly 
with the fibres of the genio-hyo-glossus, into the body of the tongue 
near its centre. Externally it is covered by the hyo-glossus and 
the stylo-glossus longus muscles ; and internally it covers the lin- 
gual artery and the genio-hyo-glossus muscle. In its action it 
combines the uses of the stylo-glossus and genio-hyo-glossus ; with 
the former retracting the tongue, and with the latter depressing the 
central line, and rendering it concave for the safe passage of fluids 
towards the pharynx. 
