THE SENSE ORGANS 



147 



THE PROJECTILE NOSE 



Whereas the olfactory ridges and Jacobson's organ of Man 

 are to be considered degenerate, the projectile nose and its 

 skeletogenous supports are in a progressive condition ; they may 

 indeed be considered as specifically human structures. It cannot 

 as yet be said with certainty what gave the first impulse to their 



FIG. 90. HEADS OF TWO HUMAN EMBRYOS. 



A, at the end of the second ; B, at the beginning of the third month (after W. His), 

 aw., external auditory involution, with the pinna (p.) seen developing around it. vs., 

 eye ; ol., nose. 



development. 

 inquiry. 1 



This question awaits an extended morphological 



THE EYE 



The human eye itself shows few vestigial structures ; and 

 these, being limited to the embryo, are but transitory. I refer 

 to the arteria hyaloidea which passes through the vitreous body 

 within Cloquet's canal, and which is closely related to the fcetal 

 choroidal fissure! The former plays an important part in the 

 nutrition of the central part of the eye during embryonic life. 

 This is provided for in Fishes and Keptiles by organs known as 



1 This has been undertaken by my pupil F. Spurgat, and a preliminary report on 

 his first series of observations will be found in the Anal. Anzeigcr, Bd. viii. p. 228. 



