The Sinus Maxillaris in Man. B05 
common. The ethmo-turbinal plates and the resultant furrows 
become reduced in number as development goes on, and finally 
represent the conchz nasales, media and superior, and the 
meatus nasi, medius and superior, respectively. The reduction 
in number may not be carried so far, and this accounts for the 
supernumerary ethmoidal conche and meatus in many adults. 
Enc’lon. 
Fic. 1 (X 10). Drawing of a frontal section through the head of an embryo 
aged about 45 days, in the region immediately dorsal to the organon vomerona- 
sale (Jacobsoni), note the development of the early turbinal processes, and that 
there is no cartilage laid down in them at this early period. This is contradic- 
tory to the theory that the turbinal processes are primarily the result of an 
inpushing of the lateral nasal wall by cartilaginous strands which later become 
the nasal conche. ; 
Enc’lon, = encephalon; E. T., = ethmo-turbinalia; M. T., maxillo-turbinale; 
P. Pal., = processus palatinus; Sep. Nasi, = septum nasi. 
Just how the primitive nasal processes and furrows are formed 
is interpreted differently. Some claim that the projections are 
due to an inpushing of the lateral nasal wall by the cartilaginous 
strands which become the nasal conche. This latter claim I 
have been unable to verify, because I find that the folds or 
projections are invariably present before cartilage is found in them 
