A CLINICAL STUDY OF THE SKULL. 31 



thick.' The plates as a rule conceal the backward exteusion of 

 the spheno-turbiuals, and lie over and protect the veins and nerve 

 of the canal. Thus they are apt to be pushed downward with the 

 vomerine alie in instances of unusual imperfection of the sphenoido- 

 vomerine union. 



When both the sphenoidal processes of the palatines and the vag- 

 inal processes are defective, the spheno-turbinals are seen distinctly 

 exposed, thus showing the value of the plates named in covering 

 and in strengthening the body of the sphenoid.^ 



The vaginal processes rarely extend backward beyond the vomer, 

 and evince a disjDosition to approach toward the median line.^ 



It is well to remember that it is possible to have the image of the 

 choana as seen in the rhinal mirror narrowed by thickening of the 

 internal pterygoid plate. 



The lower end of the vomer may exhibit the tendency, so com- 

 monly seen in the lower animals, of joining the palatal bones in 

 advance of the posterior nasal spine. The vomer may be fully two 

 millimetres within the nasal chambers.* I have seen it recede still 

 farther within the chambers in the living subject. The exact posi- 

 tion of the vomer becomes a matter of importance in determining 

 the degree to which the inferior turbinated bone projects from the 

 nasal chamber into the naso-pharynx. 



The wings of the vomer may be united as the bone lies against 

 the sphenoid, or a well-defined notch may be defined between them.^ 



A faint ridge is often seen extending vertically on the vomer. 

 It answers to the line of union of the sphenoidal process of the pal- 



^ 120-5, Seminole. 



"^ Examples iire seen in No. 113, Genoa, 12 years old ; 19, Ruthene, 7 years 

 old; American, No. 58, 6 years old (Col. of Phys.), and a Hindoo, aged 8 

 years, No. 32, A. N. S. No. 89 (Col. of Phys.), an adult skull of an 

 Adrian, shows the same peculiarity. 



3 No. GO, Austrian, 16 years old (Col. of Phys.). 



*13Io, Golgonda; 605, Sioux ; 1227, Blackfoot. 



544, 1220, Menominee; 106, 407, 522, 542, Miami; 952, 953, 733, Narra- 

 gansett; 207, Puget Sound Indian; 604, Seminole; 436, Chetimache ; — , 

 California Indian; 670, Chinese; and in 1205. 



