No. 3.] WUSCLES AND NERVES IN AMIA CALVA. 709 
septum, and is inserted on the inner surface of the supracla- 
vicular. In young larvae the large ligament is well developed 
and easily traced in sections ; the small ligament, on the con- 
trary, could not be distinguished from the septal tissues in 
which it lies. In one larva the large ligament lay in the 
second prespinal septum instead of in the first. 
The occipitale laterale (LO) has two exposed surfaces, a 
lateral and a dorso-posterior. The two surfaces lie almost at 
right angles to each other, and form, where they unite, the 
dorso-lateral edge of the bone and of the hind end of the 
skull. The posterior and lower end of this dorso-lateral edge is 
thickened, and rests upon, or abuts against, the anterior face of 
the anterior wedge-shaped process of the cartilaginous strip 
on the dorsal surface of the basioccipital. The occipitale 
laterale is thus separated entirely by cartilage from the solid 
vertebral portion of the basioccipital, excepting, possibly, along 
its extreme outer edge. The antero-dorsal end of the dorso- 
lateral edge of the bone is also thickened, and that portion 
of the lateral surface of the bone that lies between this thick- 
ened upper corner and the upper edge of the vagus foramen is 
raised slightly above the level of the rest of the bone, and has 
its outer surface flat and roughened. On this roughened sur- 
face, which resembles, in general appearance, the surfaces 
found elsewhere, in Amia, between the dermal and cartilagi- 
nous bones, the lower, posterior corner of the intercalar rests. 
The intercalar thus, in this particular, presents the character- 
istics of a membrane rather than of a cartilage bone. It is 
also easily detached from the skull, as the dermal and mem- 
brane bones are, and it leaves beneath it, when removed, a 
clean, unbroken surface. In larvae its first appearance is 
decidedly that of a membrane bone. Sagemehl’s positive 
statement (No. 107, p. 556) that it is, in Amia, a primary 
ossification is, therefore, greatly to be doubted. It is much 
more probable that it is of exactly the same character as the 
corresponding bone in the Cyprinidae, that is, simply a “ Deck- 
knochen.”’ 
In front of the thickened postero-ventral end, or base of the 
occipitale laterale, the ventral edge of the bone, is thin, and 
