No. 3.] CHEEK AND SNOUT OF AMIA CALVA. 437 
behind the teeth of that bone. Its anterior end adjoins mesially, 
and is bound by tissue to, the anterior end of the ethmoid. In 
its posterior part it adjoins the nasal mesially and the lachrymal 
postero-laterally. Its posterior end is directed toward, but does 
not reach, the antero-lateral corner of the body of the frontal. 
Postero-lateral to this end of the bone, between it and the 
lachrymal, is the posterior nasal aperture; the canal leading 
from that aperture into the nasal sac running mesially and 
forward posterior to and then mesial to the hind end of the 
antorbital. Between the anterior end of the bone and the ante- 
rior ends of the ethmoid and nasal is the anterior nasal aperture. 
The lateral edge of the bone is bound by fibrous or ligamentous 
tissue to the anterior end of the maxillary. The bone 1s trav- 
ersed by the proximal portion of the anterior cross-commissure 
of the infraorbital lateral canal, and encloses, perhaps, also, the 
extreme anterior end of the latter canal itself. 
The antorbital bone, as a separate bone, cannot be positively 
recognized in any of the descriptions that I have of other fishes. 
According to Bridge (No. 7, p. 609), it is described by Huxley 
in Clarias as the preorbital bone. This bone of Clarias is shown 
by Pollard in a figure intended simply to show the course of the 
lateral-line canals of that fish (No. 31, Pl. XXXV, Fig. 1), and 
is called by him the antorbital bone. He, however, says in the 
text that there is another, small, rudimentary, dermal bone lying 
in front of it, between it and the antero-lateral end of the 
ethmoid. As the lachrymal of his figure lies partly below the 
eye, and but one suborbital bone is given, his lachrymal may 
be the homologue of the first suborbital bone of Amia; his 
antorbital then being the lachrymal of Amia, and the rudi- 
mentary bone the antorbital. 
Similarly, in the Cyprinidae the several references made by 
Sagemehl (No. 37, pp. 566, 567, 587) to a preorbital bone are 
insufficient to warrant its identification as the antorbital of Amia 
rather than the lachrymal. The bone is said to be the most 
anterior bone of the “ Orbitalbogen,” thus occupying exactly 
the place of the lachrymal in Amia; and the use of the term 
preorbital instead of antorbital indicates in itself that the bone 
could not have been considered by Sagemehl himself as the 
