A CLINICAL STUDY OF THE SKULL. 41 



the lateral mass of the ethmoid bone is eaten away, and the entire 

 remaining portion of the bone is closely packed with the pupa cases. 



The Posterior Two-thirds. — While the anterior part of the middle 

 urbinal is apt to be vertical and compressed, so the posterior part 

 is often horizontal at its upper part.^ The scroll, indeed, may be 

 said to be an inferior volute from a horizontal line, as in the scroll 

 of the Ionic capital. Hence, the term turbinal is characteristic of 

 a portion only of the bone. 



The outer border of the posterior end of the horizontal part is 

 usually notched. It is probable that the notch is for the accommo- 

 dation of a vessel which is in connection with the structures occu- 

 pying the spheno-palatine foramen. Occasionally, as is seen in a 

 Bengalese skull,^ a delicate bridge of bone converts the notch into a 

 foramen. 



The ledge-like upper border of the middle turbinal may be in- 

 clined or nearly vertical. These different shapes can be indicated 

 (even when the turbinal is absent) by the direction taken by the 

 upper crest on the palatal bone.' 



In the posterior nares the ends of the middle turbinated bones, 

 in the great majority of instances, are symmetrical and more or less 

 curved. In 150 out of 234 skulls of adults examined the parts 

 are of the kind described. 



In 44 specimens the scroll presented a semicircular outline 

 thus : )l(. The curved lines represent the middle turbiuals and the 

 vertical line the vomer. Of this number, 3 exhibit the upper 

 part of the middle turbinal horizontal, instead of curved. 



The varieties in which the middle turbinals were long and placed 

 high up in the choanse are included in the list of the symmetrical 



^ The horizontal part is most likely homologous with the ledge of the 

 nasal chambers of quadrupeds where it separates the olfactory from the re- 

 spiratory tracts. 



2 No. 25. 



3 The middle turbinal may lie well within the nasal chamber, some dis- 

 tance from the plane of the posterior end of the inferior turbinal. Example, 

 No. 679, Esquimaux. 



