A CLINICAL STUDY OF THE SKULL, 27 



ined in the collection of the Academy not a single one was seen of 

 such union, while all the examples showed by the extent of the 

 groovings on the side of the body of the sphenoid bone, and by the 

 degree of convexity of the central part of the surface, that the type 

 was that of the variety described in my notes as " convex, hyper- 

 ostosed," or "open posteriorly." 



If we accept the theory that the arrangement seen in primitive 

 races is the same as in many lower animals, and therefore that the 

 earlier races of men more readily resemble the skull of mammals 

 generally, we are forced to conclude that development is more 

 rapid in the primitive races than in civilized, and that a phase of 

 development which is transient in savage races becomes permanent 

 and fixed in the civilized. 



It is not unlikely that the retention of the juvenile characteris- 

 tics in a large proportion of skulls of civilized man may be asso- 

 ciated in some individuals with enlargement of the adenoid tissue 

 at the roof of the pharynx, and that these characters of the sphe- 

 noid bone and the vomer may be due to the veins which pass fi'om 

 the mass, effecting anastomosis with the nasal venous sinuses and 

 the spheno-palatine veins, and thus tending to keep up the large 

 vascular tracks which lie between the body of the sphenoid bone, 

 its internal pterygoid plate and the palatal bone. The size of the 

 gaps left by failure of the pterygoid aud palatal plates to unite 

 with the vomer, as compared to the width of the posterula, is not 

 insignificant. (See Figs. 3, 4, 6, 7.) 



The primitive vomer is chiefly found, as above mentioned, in the 

 crania of savages, while the hyperostosed vomer with incomplete 

 sphenoidal union in those of civilized people. In addition it may 

 be said that the last-named group includes a larger number of 

 associated anatomical variations than is the case with the first 

 named — a conclusion in harmony with the statement already 

 quoted, which is attributed to Retzius, that individual differences be- 

 come greater in proportion to the higher intellectual development. 



In illustration of the lack of uniformity of description of the 

 region of the posterula the following citations are made : 



