554 ALES, [VoL. XII. 
and backward, in the direction of the muscle, to the anterior 
edge of the large tendon A;Ao”, which it joins near the hind 
edge of the splenial. Here it joins and usually fuses com- 
pletely with the tendon of the second division of the muscle, 
ILms?. The united tendons, as a broad flat band, continue 
backward and then downward in a curved line along the outer 
surface of A; Aw", closely attached to that tendon, but in no 
way fused with it. They have their own particular insertion 
on a small ossification which lies immediately behind the hori- 
zontal projecting rib of Meckel’s cartilage, and has been called 
by Bridge ossicle ¢ (No. 15, p.618). This is the only insertion 
of the muscle evident in larvae. In the adult, however, what 
seemed to be a second tendon of the muscle was always found. 
It lay on the inner surface of A; Aw", as shown in the 
figures (Figs. 41 and 42, Pl. XXX), and had its insertion pos- 
terior to the insertion of the united tendons of Laws3 and Lms?, 
apparently on the same bone, ossicle ¢, at its extreme edge, or 
possibly on ossicle 6. This could not be definitely determined. 
The tendon always had much the character of a string of con- 
nective tissue, but it was always found well defined through 
the greater part of its length. At its insertion it was always 
joined by parts of the posterior portion of tendon 4; Ao”. 
In larvae, Zs3 arose entirely from the upper surface of 
the palatine cartilage, and in no instance had it acquired any 
attachment to the antorbital process. In one instance it was 
double throughout its length, arising, one part a little in front 
of the other, on the upper surface of the palatine, the two 
divisions lying side by side and contracting separately into 
separate tendons, which united to form a single tendon just 
before reaching the large tendon of the adductor. In several 
other specimens there were indications of such a division into 
two parts, but there was no actual separation of the fibres. 
The second and first divisions of ws arise, in the adult, as a 
single muscle, mainly from the front edge of the hyomandibular 
at its extreme upper end, but the line of origin extends forward 
from the hyomandibular, across the upper end of the lateral 
wing of the parasphenoid, to the front edge of that bone. 
In young specimens also, of from 20 mm. to 40 mm. in 
