316 Jacob Parsons Schaeffer. 
(fig. 1). The elevations at first consist of a duplication of the 
ectoderm filled with indifferent mesenchyma, which, in part, later 
changes into cartilage. Thenasal conchal cartilages are, therefore, 
a result and not a cause of the early condition. Schoenemann 
claims that they are elevations left by excavations of furrows 
on the lateral wall of the nasal fossa. Killian and Mihalkovies 
hold that the projections are free ingrowing folds on the lateral 
wall of the nasal fossa. Glas concludes a discussion on the nasal 
conche in rats thus: 
Die Bildungsmodus der Muscheln, ist die Resultierende zweier 
Komponenten; (1) des Auswachsens die Wandpartien einwachsender 
Epithelleisten (Fissuren). (2) des Vorwachsens bestimmter Wand- 
partien. 
After a study of these early conditions I am led to believe that 
the primitive furrows are primarily the result of an outpushing 
or outgrowing of the mucous membrane on the lateral wall of the 
nasal fossa. The projections, by duplication of the mucous 
membrane (especially true in the ethmo-turbinal region) (fig. 1), 
and the deepening of the furrows, become rapidly prominent. 
At times the two processes, an outgrowth or outpushing, and a 
duplication of the intervening mucous membrane and mesen- 
chyme, seem to be at work simultaneously in forming the early 
projections and furrows. The theory that the furrows are 
primarily started as an outpushing or outgrowing of mucous mem- 
brane is entirely in accord with, apparently, similar processes 
taking place in the early embryo nose; namely, the pouching or 
outgrowing of the mucous membrane as the Anlagen of some 
of the sinus paranasales. That a similar process should cause 
the formation of primarily similar outgrowths seems plausible. 
It is, however, not the province of this paper to speak in detail 
of the development of the early projections and furrows; suffice 
it to say that it is from the furrow separating the primitive 
conche nasales, inferior and media, that the maxillary pouch 
evaginates. It is, therefore, the primitive meatus nasi medius 
with its contained structures, and the naso- and first ethmo- 
