a ee 
' 
THE MYOLOGY OF AMIURUS CATUS. oun 
(g) Arises immediately in front of the last, and is inserted into the 
upper surface of epibr. i, near its inner extremity. 
Innervation.—(a) Is supplied by 
(6) by a branch from tr. branchialis 2. vagr; (c), (d) and (e) by branches 
from tr. branchialis iw. vagi; (f) by branch from coalesced tr. 
branchialis i. and ii., and (g) by a branch from the glossopharyngeal. 
Action.—(a) By drawing the posterior part of the pharyngeal up- 
wards, depresses its anterior portion ; (c) and (d) act together, raising 
the anterior border and depressing the posterior, and at the same 
time the fibres of (d) will raise the outer border somewhat. These 
muscles impart a rocking motion to the superior pharyngeal, which 
must be very effective in grinding the food against the inferior 
pharyngeal ; () draws the arches upwards and backwards, depressing 
the posterior ones ; (¢), (f) and (g) draw the arches directly upwards. 
Vetter describes these muscles into two groups, ‘ internal’ and 
‘external.’ The latter in the Cyprinoids are five in number, in 
sox three. They are inserted in the former into the pharyngo-brs. 
i., ii, lii. andiv., the three posterior sending a small slip to the epibr. 
i., li. and iii., respectively. The fifth muscle is inserted into the pos- 
terior portion of the superior pharyngeal, and is therefore equivalent 
to (a). The external muscles are three, being inserted into the phary- 
ngobrs. li. and iii., and epibr. iv. It would be difficult to homolo- 
gize the arrangement in Amiwrus with that of the other described 
forms, but it is to be noticed that in the former the superior phary- 
ngeal receives three muscles but only one in the latter. 
7. Muscuut INTERARCUALES OBLIQUI DORSALES. 
These are exposed by the same dissection as the preceding, which 
must also be removed. They are three in number. The first arises 
from near the inner extremity of the posterior edge of epibr. i., and 
runs back above and slightly exterior to the second, to be inserted 
into the anterior edge of the upwardly directed process of epibr. iii. 
The second, large and stout, lies below the first. It arises from the 
posterior border of epibr. ii., near its inner extremity, and is in- 
serted into the extremity and anterior edge of process of epibr. 
iii. The third arises from the inner extremity and anterior edge of 
the pharyngobrs., between the third and fourth arches, and, pass- 
ing back, is inserted into the extremity and anterior edge of the 
process on epibr. iv. 
