452 ALLIS. [Vou. XIV. 
According to Pollard’s figures (No. 30, Figs. 12 and 15), it lies 
ventral to the anterior end of the chondrocranium, but not 
external to the ethmoid either on the dorsal or the ventral sur- 
faces of the skull. The hind ends of the ventral plates of the 
two bones, in Pollard’s figures, approach the anterior end of a 
median, dermal bone, called by him the subrostral (No. 30, 
p. 412). This latter bone bears teeth and is said to lie ventral 
to the anterior end of the parasphenoid, between the posterior 
parts of the adjoining antero-mesial ends of the so-called 
vomers. If the ventral plates of Pollard’s premaxillary bones 
should fuse with the subrostral a ventral plate would be formed 
the exact equivalent of the ventral plates of the premaxillaries 
of Traquair’s descriptions, fused in the median line with each 
other. 
The single subrostral of Pollard thus seems to be the homo- 
logue of the vomers of Amia fused with each other and greatly 
reduced in size. In Traquair’s specimen, as in Amia, these 
two halves of the subrostral seem not to have fused with each 
other. They have, however, completely fused with the pre- 
maxillaries, instead of only partly so, as in Amia. 
The premaxillary bone of Polypterus, as shown by Traquair, 
has two ascending processes—a small one, mesial to the 
anterior nasal aperture, and another, much larger one, lateral 
to that aperture and lateral also to the posterior nasal aperture. 
In teleosts the ascending process of the premaxillary, which 
is, according to Sagemehl, rarely wanting (No. 36, p. 99), arises 
from the mesial end of the horizontal alveolar portion of the 
bone, lies mesial to the anterior nasal aperture, or wholly in 
front of it, and is bound directly or indirectly to the anterior 
end of the skull. Where it is bound indirectly to the skull by 
the intermediation of a separate cartilaginous rostrale, that 
element lies external to the ethmoid bone, or external to the 
ethmoidal region of the chondrocranium. In the Cyprinidae, 
where the ascending process is small, it is bound to the ante- 
rior end of the skull by a fibrous band, in which there is almost 
always a small median bone which Sagemehl considers as the 
ossified rostrale (No. 37, p. 584). 
In Urodela (No. 27) the ascending process of the premaxil- 
