1869. | MYOLOGY OF MENOBRANCHUS LATERALIS. 459 
Omo-hyoideus (figs. 3, 4, & 5, O.H). This elongated muscle 
avises from the inner and upper side of the precoracoid cartilage, 
and passes thence forwards to between the urohyal and first bran- 
chial arch. 
Genio-glossus*. This small muscle arises, on each side, from the 
posterior surface of the mandibular symphysis, and thence passes 
outwards and backwards to be inserted into the skin of the mouth. 
The levatores brunchiarum+ are small muscles which pass down- 
wards from the dorsum of each branchial arch respectively to the 
dorsum of each gill-tuft. 
The depressores branchiarumt go from the ventral surface of 
each branchial arch to the ventral surface of each gill-tuft re- 
spectively. 
Of the adductores branchiarum§, the first goes from the dorsal 
end of the second branchial arch to the first gill-tuft ; the second 
similarly from the third branchial arch to the second gill-tuft ; the 
third, long and delicate (fig. 3, 4. B), extends from the angle be- 
tween the precoracoid and scapular cartilages forwards to the root 
of the third gill-tuft and dorsal part of the last branchial arch. 
APPENDICULAR MUSCLES. 
Pectoral Limb. 
Trapezius (fig. 3, Tz). This is an exceedingly small muscle, 
which is placed immediately behind the third adductor branchiarum 
aud levatores arcuum. It arises from the fascia investing the 
dorsal muscle, and is inserted into the lower half of the anterior 
margin of the scapula down to its junction with the precoracoidal 
cartilage. 
The Jatissimus dorsi (fig. 3, Z..D) is more than twice the size 
of the trapezius. It arises from the fascia, and ends by coalescing 
with the upper part of the triceps. 
The pectoralis (fig. 4, P. 1 & P.2)is a considerable muscle which 
arises partly from one of the tendinous intersections of the rectus, 
partly trom a raphe separating it from its fellow of the opposite side, 
and partly from the under surface of the posterior part of the 
coracoidal cartilage towards and at its inner margin. It is inserted 
into the lowest part of the crest of the humerus, immediately above 
the origin of the biceps. The part arising from the coracoid (P. 2) 
is slightly separated from the larger and more posteriorly arising 
portion (P. 1). 
Serratus magnus. This is a thin small muscle springing from 
the side of the lateral muscular mass beneath the Jatissimus dorsi. 
It is inserted into the inner side of the upper part of the scapula. 
The levator anguli scapule is a very long and slender muscle. 
* Fischer, /. ¢. p. 67. 
+ Fischer, Zc. p. 38, and tab. iii. 6, 7b’, 1b’, 1b’. 
{ L.e. p. 39, and tab. i. fig. 1, db', db’, db”. 
§ Lic. p. 39. 
