458 ALLIS. [Vou. XIV. 
palate plate of the superior maxillary; and that the vomer bone 
or bones of fishes, other than Polypterus, are represented either 
in that horizontal piece which, according to Sutton, projects 
backward, in man, from the mesial surface of the premaxillary 
part of the superior maxillary bone, and forms the inner bound- 
ary of the anterior palatine canal; or in some part, but not the 
whole, of Sutton’s prepalatine part of the hard palate. The 
primary relation that the vomer is said to acquire to the chon- 
drocranium in certain fishes (No. 36, p. 40) is, then, simply 
repeated in the similar relation said by Sutton (No. 42, p. 569) 
to be acquired by a part of the premaxillary bone of man. 
The vomer bone of fishes not being the homologue of the 
vomer of man, it remains to seek in the former animals the 
homologue of the latter bone. According to Sutton, it is to be 
found in the anterior end of the parasphenoid. According to 
Pollard’s supposition, it would be represented by the dermo- 
palatine. According to Erdl (No. 13), it is represented by the 
so-called ethmoid. But for the fact that the septomaxillary of 
Amia is preformed in cartilage, and not in membrane, it would 
seem to fulfill even better than any of these bones the conditions 
of a mammalian vomer. It rests directly upon the piscine 
vomer, the probable homologue of a part of the palate plate of 
the superior maxillary bone of man; and it articulates with the 
palatine, thus coming into relations both with the auto- and the 
dermo-components of that bone, the latter of which is probably 
the homologue of the horizontal plate of the palate bone of man. 
If the nasal septum were to become gradually thinner, the septo- 
maxillary would, if retained, naturally extend upward and back- 
ward, in the septum, toward the ventral edge of the primary 
ethmoid, which bone is generally considered as the homologue 
of the vertical plate of the ethmoid bone of man, and which, 
in teleosts, ossifies downward from the dorsal surface of the 
snout. 
Bearing the several homologies here indicated in mind, 
imagine the snout of Amia pushed backward between and below 
the eyes, under the anterior end of the cerebral cavity, where 
it is found in man. Imagine, also, the cartilaginous floor of 
the nasal cavities absorbed; the vomer reduced in length 
