440 CRANIA FROM THE MOUNDS OF FLORIDA. 



It is seen from this table that in the lower molars the presence of four cusps 

 characterizes the majority of teeth in the second tooth only. In the first molar the 

 presence of a commissural cuspule toward the outer side (making three cusps on the 

 outer side for two on the inner) is seen in over one-half. The number is practically 

 the same on the two sides. The normal arrangement for the first molar charac- 

 terizes less than one-sixth of the whole ; while in the third molar the order is again 

 different. 



(3). The cuspidation of the upper molars. The cuspidation of the second 

 upper molar may be taken as the most important variable for the reason that the 

 first molar is never possessed of less than four cusps or more than five, and the third 

 molar is so irregular that its characteristics are not likely to yield facts of 

 importance. 



The second molar is usually made up of four cusps, but it may have three 

 cusps with a rudimental fourth, or have three cusps only. Observations on fifty 

 inmates of the Penitentiary resulted in the following : — Four cusps, 30 ; three cusps 

 and rudimental fourth, 7 ; three cusps, 13. 



In the collection of the Academy of Natural Sciences of Philadelphia, one 

 hundred skulls were examined (all modern Europeans being excluded) with the 

 following result : — Four cusps, 26 ; three cusps and rudiments of a fourth, 29 ; 

 three cusps, 45. It is thus seen that the rates of cuspidation differ in the series from 

 criminal subjects and those from specimens found in a miscellaneous collection 

 composed for the most part of uncivilized peoples. 



Only one example of a second molar exhibited five cusps of which the supple- 

 mental cusp was in the form of a cingule to the paracone. The first molar in two 

 instances only possessed less than four cusps, while in four instances it possessed the 

 supjalemental palatal cusps, thus making the entire number five. 



The third molar is so variable that it cannot well be classified. In only three 

 instances did it possess four cusps ; in eight instances only did it retain three cusps, 

 while in the remaining ten instances it was irregular ; by which term is meant a 

 departure from a polycuspidate form and exhibiting various crenulations and depres- 

 sions which do not admit of arrangement. Some of these closely resemble the plan 

 of a premolar ; others are depressed in the centre and bordered by a folded hem, 

 this I have called in my notes the crater-like tooth ; some of the teeth have three 

 mammillations arranged in order from without inward. 



The third molar infrequently retains the cuspidation of the first and second. 

 The protocone and paracone can be named as a rule ; the cingule, from which the 

 metacone and hypocone, arise often complete the tooth. As already shown occasion- 

 ally the metacone. will be developed at the expense of the hypocone ; sometimes 

 the contrary takes place, but in either event the division of the crown by the size 

 of the several parts rather than by homology results in the protocone and paracone 

 forming almost the entire crown. 



(4). The order of succession of cusps. In 1875 1 I announced that a true 

 development occurs from the canine and incisor series toward the molar by means 



1 Dental Cosmos. 



