34 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
2. MUSCLES OF THE TONGUE. 
The tongue musculature consists of a set of longitudinal muscles 
and an interlacing system of intrinsic fibers inserted on its mucous 
membrane perpendicularly to the surface. The longitudinal muscles _ : 
consist of m. genioglossus (gen-gls.) and some others, to which specifie 
names will not be given. The genioglossus muscle is a paired structure 
having its origin along a considerable extent of the cerato-branchial I, 
(Plates 5-7, figs. 13-22; Fig. E). These bands passing forward form 
rounded bundles extending the full length of the tongue and are more 
or less surrounded by the other tongue muscles. Ventrally, however, 
. OM0-hy prF 
SPhi. coll. ‘ :OMONY, ie ker-md. 1 
er-md. 2 
tT — = eee 
FS 
\yE hy, 
See ml: “hy. 
Fic. E.— Ventral aspect of head and neck after complete removal of the 
mm. mylo-hyoideus, sphincter colli, cerato-mandibularis 1 and 2, and 
omo-hyoideus (superficialis). The m. omo-hyoideus profundus and the 
m. cerato-mandibularis 1 of the left side remain to show more clearly their 
position and extent. The origin of m. cerato-mandibularis 2, indicated 
by dotted lines, covers that of a part of the longitudinal tongue muscle. 
they are bounded by large lymph sinuses, which leave the tongue 
attached by only its lateral muscular walls and thus permit its free 
movement and change of form (Plate 4, figs. 9-11). 
Two other longitudinal muscles may be recognized. ‘These are not 
separable in their origin, but differ in their anterior attachment. 
They arise on the ventral face of the genioglossus (Fig. 2) at about 
the level of the larynx, and the bundles are increased by fibers springing 
apparently from the connective tissue underlying the mucous meti- 
brane lateral to this muscle (Plate 5, fig. 12, Ing. lg.) Passing forward 
this divides into two bundles with different relations to the tongue. 
