228 EDWARD PHELPS ALLIS, JR. 
tween the ventral ends of the ventral processes of the prootics. 
This opening is the hypophysial fenestra of Sagemehl’s descrip- 
tions of Amia and the Teleostei, and I have always employed 
that term for it in all my works. This fenestra has, however, 
in a considerable part of its length, no relation whatever to the 
hypophysis, and it will be later shown that, in all probability, 
it does not even contain the so-called fenestra hypophyseos of 
early embryos of these fishes. The term hypophysial fenes- 
tra is thus inappropriate, and I shall hereafter refer to it as 
the fenestra ventralis myodomus. To facilitate the descriptions 
and comparisons, the ventral processes of the prootics will be 
considered to be ventrolateral vertebral processes, notwithstand- 
ing that this is not definitely established by my present work. 
SCOMBER SCOMBER 
In the adult Scomber I found (Allis, 03) the myodome ex- 
tending nearly to the hind end of the basioccipital but not open- 
ing posteriorly; and, doubtless in direct correlation with this, 
the parasphenoid of this fish does not have diverging hind ends. 
That part of the myodome that is related to the basioccipital is 
enclosed between ventral flanges of that bone which closely re- 
semble the ventral processes of the prootics and form a direct 
posterior continuation of them. Two membranes, one vertical 
and the other horizontal, were said to extend the full length of the 
myodome. The horizontal membrane was said to separate the 
myodome into dorsal and ventral parts which lodged, respec- 
tively, the recti externi and interni. The vertical membrane 
was said to arise from the hind edge of the pedicel of the basi- 
sphenoid and, lying between the recti interni, to bisect the ven- 
tral part of the myodome. ‘The recti inferiores were said to arise 
partly from the interorbital septum, between the foramen op- 
ticum and the anterior edge of the basisphenoid, and partly 
from a ligament or tendon which arises from the dorsal end of 
the pedicel. of the basisphenoid. The recti superiores were said 
to have their origins from the anterior edge of the horizontal 
membrane. 
