700 ALLIS. [VoL. XII. 
ligament in Amia, as Vetter does the muscle in Acipenser, the 
coraco-arcualis anterior¢. 
The branchiomandibularis, in Amia, varies greatly in different 
individuals. The posterior portion of the muscle, both in old 
and young specimens, is as often single as double, the insertion, 
when single, being to one arm only of the Y-shaped tendon, no 
trace of the other arm of the muscle being found. In some 
instances the second arm of the muscle is found reduced in 
length, and ending without insertion of any kind, and in one 
specimen both arms were wholly wanting, the muscle ending, 
without insertion of any kind, a little beyond its neck. The 
anterior portion of the muscle, which usually, in the adult, has, in 
part, a tendinous insertion on the inner surface of the mandible, 
sometimes extends only as far as the intermandibularis, and in 
larvae it can never be traced definitely beyond that muscle. 
The anterior, tendinous portion of the superior division of the 
geniohyoideus, that portion that has its insertion on the mandi- 
ble, can also not be traced in larvae. In 10 mm. specimens, the 
branchiomandibularis extends but little beyond the large vas- 
cular space through which the muscle passes, and is there lost 
in the general tissues. In one young specimen it passed above 
the fold in the lining membrane of the mouth cavity at the base 
of the tongue, instead of below it, as it is usually found, and 
was lost in the connective tissues toward the tip of the hyoid 
and at the base of the tongue. It seems therefore prob- 
able, that the tendinous insertions of the geniohyoideus and 
branchiomandibularis on the inner surface of the mandible are 
acquired in postlarval, or even in adult life, Acipenser (No. 125, 
p. 480), where the branchiomandibularis is firmly attached to 
the integument of the floor of the mouth, representing an 
intermediate stage. The general relations of the branchioman- 
dibularis to the tongue, in larvae, and the actual termination 
of the muscle in one young Amia in that organ, seem also 
to corroborate McMurrich’s statement (No. 76, p. 152) that 
that muscle, in lower forms, corresponds to the muscle from 
which the tongue muscles of Amphibia are developed. The 
tongue of the adult Amia may, therefore, represent a condition 
of that organ in which its partial muscularization has been lost, 

