392 THE NASAL REGION IN EUTAENIA. 
plates, one to proceed down the outer surface of the Organ of Jacob- 
son, the other, to proceed in opposite direction, on the outer wall of 
the passage and terminate in the middle of its height. The lower 
plate is found in other sections to enter the pedicle (Fig. 2, pd,) of 
the Organ of Jacobson, and partly fuses there with the basal portion 
of the vomer. In the section represented it does not so enter, its. 
place being occupied by the cartilage which passes out from the 
pedicle and lines the outer under face of both plates of the septo- 
maxillary, and ultimately in sections behind this reaches the turbinal 
ingrowth, with the cartilage of which it unites, (Figs. 2, 3, 4, tb.) 
The upper half of the pedicle is filled with cartilage throughout, 
(tb’ 2, 3.) The turbinal cartilage extends over the nasal cavity to- 
connect in front with the wing of the nasal septum, which terminates 
inferiorly with a rounded edge between the cupped crests of the 
vomer of each side. (Figs. 2, 3, 4, Sept.) 
In a section through the anterior termination of the maxillae, the 
latter with the premaxilla form a horizontal plate with a plate of 
cartilage, also horizontal, in its centre. Im a section behind this. 
the cartilage is concave on its upper face, and the osseous 
piece above it, is the ascending process of the premaxilla. Below,, 
are two basal pieces, not distinctly separated from each other, or 
from the maxillae now somewhat laterally. Behind this again the 
cartilage takes a U form, the wings of which give off on each side a. 
nearly vertical transverse plate, forming a prenasal wall, and reach- 
ing the cheek in front of the anterior nasal opening. Between the 
wings of the main cartilage, now the nasal septum, the ascending 
process of the premaxilla extends and forms a vertical plate. (Fig. 
6, pra.) Immediately behind the transverse prenasal wall of each 
side, the septomaxillary commences rod-like, and separated from the: 
similarly shaped vomer by a thin sheet of cartilage continuous with 
the transverse prenasal wall. The basal portions of the premaxilla 
(prb) do not extend much further behind this point. The septo- 
maxillary becomes flattened as it proceeds backward, its transverse 
axis directed outward and downward, and applied in this manner to: 
the wall of the nasal cavity. It is still separated by the cartilage, 
above described, from the vomer. When the Organ of Jacobson is 
reached, the septomaxillary has acquired considerable thickness and 
forms its anterior wall, while the cartilage enters the pedicle, in the 
anterior half of which the two mentioned bones fuse, although incom- 
