ha2 EDWARD PHELPS ALLIS, JR. 
current nasal aperture, the process a not however entering the 
nasal flap or being capable of being turned back as shown in 
Gegenbaur’s figure 6, plate 17. The process a’ of this figure of 
Gegenbaur’s projects internally and orally into the nasal capsule, 
and, together with the adjoining lateral portion of the ala nasalis, 
forms a broad plate which supports the internal and aboral surface 
of the incurrent aperture, the aperture thus being a short funnel- 
shaped passage which inclines from without orally and is consid- 
erably contracted internally. The excurrent aperture is a similar 
short and funnel-shapetl passage, but the funnel is here inverted, 
the smaller end lying at the external end of the passage, and the 
passage is directed from without aborally and hence in the oppo- 
site direction to the incurient passage. The external and aboral 
wall of the excurrent passage is supported by a broad and stout 
plate which forms that part of the aboral limb of the ala nasalis 
that lies mesial to the process a, the oral edge of the passage 
being bounded by that short portion of the oral limb of the ala 
nasalis which hes mesia! to the process 6. A short prong-like 
process rises from the outer edge of the ala nasalis immediately 
lateral to the process a, and, projecting ventrally (externally) 
and aborally, abuts against the internal surface of the nasal 
latero-sensory canal, apparently being developed in supporting 
relation to that canal. 
The nasal flap arises from the free orally directed edge of the 
process a of Gegenbaur’s figure, and from the corresponding edge 
of that part of the ala nasalis which lies mesial to that process, 
and, projecting laterally and orally, rests upon the tissues cover- 
ine the base of the process 8. The processes a’ and 6 project 
uiwerd toward each other and are each clothed with mucous 
membrane which is prolonged mesially beyond the process, the 
mucous folds thus formed being apposed, valve-like, so as to 
form, in part, a roof to the Schneiderian membrane and, in part, 
to separate the two nasal passages from each other.. The base 
of the process a is connected with the process a’ by a thin fold of 
mucous tissue, this still farther separating the two nasal passages 
from each other. 
