No.5: CHEEK AND SNOUT OF AMIA CALVA. 447 
the septomaxillary. This bone in the frog is said by Parker to 
be something “more than half a tube, lining the front of the 
nasal passage and sending down a curled process, which can 
be seen from the palate” (No. 25, p. 175). On the dorsal sur- 
face of the skull the bone is said by Parker to be seen “asa 
little grain of bone jammed in between the nasal process of 
the premaxillary and the facial plate of the maxillary, in front of 
the outer nostril.” Sagemehl, although accepting in the fishes 
described by him the name given by Bridge to the bone in 
Amia, questions its homology with the similarly named bone 
of the frog (No. 35, p. 204). Both he and Bridge assert the 
homology of the bone in Amia with a well-known bone in 
Esox, that bone being bone 3 of Huxley’s descriptions (No. 21, 
p. 133). 
The septomaxillary of Amia is an ossification that begins on 
the outer surface of the cartilage of the chondrocranium, and 
extends into it from the point, or line, where the chondrocranium, 
in larvae, gives articulation to the anterior end of the maxillary 
bone. In the adult fish this articular surface is formed by the 
straight anterior edge of the septomaxillary, the bone present- 
ing posteriorly, toward and in the cartilage, a rounded and 
roughly semicircular outline. The dorsal surface of the bone is 
covered wholly, or in part, by the posterior process of the pre- 
maxillary, which lies directly upon it. The ventral surface of 
the lateral edge of the bone forms the anterior end of a low, 
longitudinal, condylar eminence, which extends backward along 
the ventral surface of the lateral edge of the antorbital process 
of the chondrocranium, and gives articulation to the palato- 
quadrate arch. 
In the Cyprinidae (No. 37, pp. 510, 582) the long and single 
palato-quadrate articular eminence of Amia is represented by 
two condylar processes, the anterior of which is said by Sage- 
mehl to be entirely of cartilage in certain species, and partly 
ossified in others. The ossification, where this process is partly 
ossified, is considered by Sagemehl as the homologue of the 
septomaxillary of Amia, and its articular surface is said to be 
always capped with cartilage. The process, although said to 
be a “‘Vorsprung”’ of the vomer, has, in the figures, decidedly 
