CRANIA FROM THE MOUNDS OF FLORIDA. 421 



Great differences are noted between the alveolar arches in respect of the 

 depth of the transverse arch of the palate. As a rule the hyperbolic form is 

 associated with high alveolar arches ; and a disposition in the premaxillaiw por- 

 tion of the palate to be thickened so that the depth of the alveolus back of the 

 incisor and canine teeth is not much less than it is at the premolars and the molars. 

 The palate being deep directly behind the incisors, compels these teeth to become 

 vertical ; on the other hand, the palate being shallow back of the incisors compels 

 them to assume an oblique position (outward and downward). Thus phases of 

 orthognathism and prognathism are established, and a reason sustained for measur- 

 ing the height of the alveolar processes. 



The palate exhibits in the middle line a tendency in the bones to be 

 hyperostosed. This eminence has received the name of the torus palatinus. I 

 have ventured to define two of these ridges which I name the pre-torus and the 

 post-torus. The pre-torus is confined to the hard palate midway between the point 

 of the premolars and the incisive foramen. The post-torus answers to the ridge as 

 named by anatomists and is seen on the hard palate from a point midway between 

 the premolars to the end or near the end of the horizontal palatine processes. In 

 No. 1,261, New Hollander, the two ridges are fused, but this is infrequently the 

 case. The pre-torus is more commonly absent than the post-torus, and both are 

 more common in females than in males. The torus palatinus is often seen in 

 Esquimaux crania, is frequent in Sandwich Islanders, while not rare in North 

 American Indians. 



(7). The guttural region. The main points of interest of the norma basilaris 

 relate to the guttural region, namely, that at the pterygoid processes and extending 

 thence backward to include the pars pet 'ros a. 



Four subjects are here presented for consideration : (a) the pterygoid and pyra- 

 midal processes ; (b) the degree of inflation of the petrosa ; (c) the foramen lacerum 

 medium ; (d) the line of the petro-sphenoidal fissure and squamoso-tympanic suture. 



(a). The pterygoid and pyramidal processes are of interest from the fact that 

 the degree of depth of the pterygoid fossa, the length of the external pterygoid 

 plate, the length of the pyramidal process of the palatal bone are exceedingly 

 variable. The assumption is made that since these characters are of value in tax- 

 onomy that the variations seen to take place in man may be useful. Two main 

 types can be distinguished, namely, one in which the fossa is shallow, the pterygoid 

 plates not extending and the pyramidal process small and blunt. This is the 

 phase seen in immature skulls and is doubtless, when met with in mature forms, an 

 example of paedomorphism (see p. 368) for lengths of pyramidal processes. The 

 other type of fossa, in opposition to the foregoing, is deep, with a wide external ptery- 

 goid plate and a long pyramidal process. In its marked form it leads to the junction 

 of the external pterygoid plate and the spinous process, and to the creation of the 

 pterygo-spinosal foramen} The spinous process, as a rule, uniting in a conspicuous 



1 The pterygo-spinosal is the same as spheno-pterygoid foramen of writers. The term spheno- 

 pterygoid is without significance. A figure in illustration is given by W. Matthews, "The Human 

 Bones of the Hemenway Collection in the U. S. A. Med. Mus., Memoirs Nat. Acad, of Sciences. 7th 

 Memoir. 



