326 PROCEEDINGS OF THE CANADIAN INSTITUTE. 
5. PHARYNGO-CLAVICULARIS INTERNUS, (No. 37, Cuv.; Branchi- 
retractor, Ow.) (Fig. 4, Ph. In.) 
A thin band-like muscle, arising from the upper surface of the 
clavicle near the middle line, and is inserted slightly behind the 
preceding. 
Innervation.—Same as preceding. 
Action.—Same as pharyngo-clav. ext. 
B.—Dorsau Muscties. 
6. Muscurt Levatores Brancuiaues, (Nos. 30-33, Cuv. ; Branchi- 
levatores and Masto-branchialis, Ow. ; Lev. branch. ext. and int., 
Vetter. ) 
These may be exposed from the inside by the dissection required 
for the pharyngo-claviculares, or from the outside by removing the 
opercular and hyomandibular apparatus and detaching the membrane 
extending from the upper moieties of the gill arches to the under sur- 
face of the skull. They are seven in number, three being attached 
to the superior pharyngeal. 
(a) Arises from a concavity on the posterior part of the under sur- 
face of the pterotic. It isa round, stout muscle, which passes almost 
directly downwards, and is inserted into the posterior portion of the 
upper surface of the superior pharyngeal. 
(6) Arises from the under surface of the pterotic in front of (a). 
It is broad and thin, and runs obliquely forwards to be inserted into 
the cartilages at the extremity of epibr. 1. 
(c) Arises from the pterotic in front of and slightly lower than 
(6). It passes down between epibrs. i. and iii., and is inserted into. 
the anterior portion of the upper surface of the superior pharyngeal. 
(d) Arises from the sphenotic immediately below the articulation 
of the hyomandibular. It passes down between epibrs. ii. and Iii, 
and is inserted just behind (c) (with whose fibres it intermingles some- 
what below) into the antero-external portion of the upper surface of 
the superior pharyngeal. 
(e) Is closely related to (d) lying on its outer surface. They arise 
together, and (e) passing downwards, is inserted into epibr. iii. at the 
base of its process, 
(/) Arises in front of (d) and (e) from the sphenotic, and is inserted 
into the inner extremity of the anterior surface of epibr. 11. 
