No.3.] CHEEK AND SNOUT OF AMIA CALVA. 461 
vertebrates must be entirely enclosed before the maxillary and 
premaxillary bones begin to develop, the premaxillary develop- 
ing, after the enclosure of the sac, in the mesial lip of the pit, 
the maxillary in the lateral one. The incisor foramen is then 
simply a persistent part of the primary nasal groove. 
The infraorbital bones of Amia, or, if the prefrontal of fishes 
is the homologue of the lachrymal of man, the infraorbital bones 
with the lachrymal, would become the malar bone. 
The septomaxillary, if it did not disappear or become part of 
the superior maxillary bone, would be forced into the nasal 
septum and become the vomer bone. Or, if the septomaxillary 
does not become a vomer, the anterior end of the parasphenoid 
might become that bone, as Sutton concludes. 
The anterior branch of the ramus palatinus facialis, which 
lies, in larvae of Amia, directly against the ventral surface of 
the chondrocranium, would, as the floor of the nasal fossa 
disappeared, enter the fossa and lie along the external surface 
of the septomaxillary or the corresponding surface of the 
parasphenoid, according as one or the other of these bones 
becomes the vomer; just as the naso-palatine nerve in man does 
along the external surface of the vomer. 
The posterior branch of the ramus palatinus facialis of Amia 
(No. 3, p. 619) runs outward and downward, inferior to the 
persisting cartilaginous part of the palato-quadrate arch, inferior 
to the auto-palatine, superior to all the dermal bones of the pala- 
tine arch, and then ventral to the horizontal articular end of the 
maxillary bone, and ventral to the premaxillary. It would thus 
lie in front of the assumed future horizontal plate of the palate 
bone and behind and then ventral to the future horizontal plate 
of the superior maxillary bone, just as the large anterior palatine 
nerve does in man. It would, however, lie internal to the auto- 
palatine, the future vertical plate of the palate bone, exactly the 
contrary to what is foundin man. The nerve in Amia, however, 
varies greatly in its relation to the auto-palatine, sometimes 
piercing that bone and issuing on its dorsal surface, and, if van 
Wijhe’s figure jis correct (No. 47, Fig. 11), lying sometimes 
wholly dorsal to it. The nerve would in these latter cases lie 
between the future vertical plate of the palate bone and the 
