376 EDWARD PHELPS ALLIS, JR. 
its contact with the suborbitals, postorbitals, and preoperculum, 
excepting only along the ventral end of the latter bone. There 
was thus apparently no supralabial furrow in these fishes. 
The ventroposterior corner of the maxillary projects ventro- 
posteriorly and forms a process-like portion which overlaps 
externally the dorsal edge of the mandible, there covering the 
quadratomandibular articulation. The ventral margin of the 
bone is furnished, throughout its entire length, with teeth. In 
Palaeoniscus these teeth are said to be very small and to be 
closely set, the more internally placed ones being larger than the 
external ones. In certain other genera of the family there is 
said to be a set of strong and powerful conical or laniary teeth 
placed in a row internal to an outer series of closely and some- 
what irregularly placed smaller ones. The ventral portion of 
the bone is said by Traquair to be slightly reflected inward so as 
to form a sort of narrow ledge, and some part of this ledge is 
said to have apparently come into contact with the ventro- 
lateral edge of a somewhat narrow and elongated bony lamina 
said to represent the palatoquadrate arch. This bony lamina is 
said to be apparently composed of two parts, one of which repre- 
sents the quadrate while the other is probably the equivalent 
of the ectopterygoid of the osseous fishes. This latter part of 
the lamina is nevertheless called the palatopterygoid, and it is 
with it that the reflected ventral edge of the maxillary is in 
contact. 
The maxillary of these fishes would thus seem to be a super- 
ficial bone that had, as in Polyodon, acquired attachment to the 
ventrolateral edge of the palatoquadrate, and the two rows of 
teeth on the ventro-internal surface of the bone would seem to 
be, one a row of holostean maxillary teeth, and the other a row 
corresponding to the inner row of teeth on the bones of the so- 
called maxillary chain of Lepidosteus or to those on the maxil- 
lary of Conger. With the disappearance of the inner row, the 
acquisition of articular connections of the maxillary with the 
neurocranium, and the development of a supralabial furrow, the 
bone of Amia would arise, while the retention of the inner row 
alone might give rise to the bone of Conger. 
