6G4 



Jacob Parsons Schaeffer, 



Frontal furroio 

 Frontaf fold. ..^^ 



Frontal furrow 



I \ ^—-^ ■'•' /» ' ' — Frontal fold- 



\ lO^v ^^-^^U ' ~^- i'^'ontalfrirrmc 



1* ^-^ 





~ Fiotttat fold ' 



\y 



— Processus uiichialns'- 



. Infiinitibiihim etiimni- 



dalf 





^ Dwliis Hiisiilai-ihiiiilis 



Fig. 37 (X 5) Drawing of a frontal section through the left nasal fossa of a 

 fetus aged approximately 7 months (seriesB, slideSl). The section isin the region 

 of the frontal recess. 



Note the frontal folds (accessory conchae) and the frontal furrows. Some of 

 the furrows, either by coalescence of the folds or by the extension of the furrows 

 towards the frontal region, end blindly and represent early anterior ethmoid 

 cells. The frontal recess is really obliterated by the coalescence of some of tlic 

 frontal folds with the lateral surface of the concha nasalis media — compare this 

 condition with that found in fig. 36 B. 



