60 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
from those of Necturus and Proteus in that the bundles of fibers are 
more widely separated from one another. This is also apparent in 
dissection. 
In treating more particularly of the muscles, they may be classified 
for convenience as follows: — 
1. Muscles of the Head 
r a. of the mandible. 
I b. of the hyoid apparatus. 
2. Muscles of the Trunk 
3. Muscles of the Fore Limb 
4. Muscles of the Hind Limb 
r a. of the trunk proper. 
) b. of the tail. 
a. of the dorsal surface 
b. of the ventral surface 
a. of the ventral surface 
r - b. of the dorsal surface 
j extrinsic. 
| intrinsic. 
\ extrinsic, 
j intrinsic. 
\ outer layer. 
( deep layer. 
j outer layer. 
I deep layer. 
Owing to lack of time, the muscles of the gill bushes, of the fore 
limb distal to the humerus, and of the hind limb distal to the femur 
have not been worked out. In some cases I could not find the 
origin nor the insertion of a muscle owing to the fact that one speci¬ 
men was already partly dissected when I received it and that the 
anterior part of the other was kept intact for sectioning. 
Muscles of the Head. 
Muscles of the Mandible. 
The muscles used in moving the lower jaw are well developed, 
and form the thick mass covering the top of the skull and the ven¬ 
tral surface of the head. 
The temjjoralis (fronto-parieto-maxillaris) arises from the mid¬ 
dorsal region of the frontal and parietal (anterior part) as a thick, 
well developed muscle, and tapers to a tendinous insertion on the 
middle third of the dorso-lateral surface of the mandible below the 
eye. 
The masseter (petro-tympano-maxillaris) a thick, oblong muscle, 
arises from the outer part of the parietal and lies parallel with the 
posterior border of the temporalis, partially covering it at its distal 
