TUTUBERCULY IX I'll I MATKS 55 



the distal or posterior intermediate cusp (///'', Fig. 38, No. 8). The term 

 is inappropriate, because this is not the fifth but the sixth cusp when \\v 

 reckon the paraconid. It is analogous to the intermediate; tulicivli-s of 

 the upper molars I have therefore suggested the term " hypoconulid " 

 for it; this cusp is almost universal among lower Eocene Mammalia; in 

 the last lower molar it forms the additional lobe ; it is found strongly 

 developed in many of the higher Primates. 



Hose (p. 406) expresses the belief that the typical form of primate 

 molar was quadritubercular as opposed to Cope's view that trituberculy in 

 human dentition is a reversion to the Lemurine type. The study of the 

 fossil forms as well as of any complete zoological series can leave no doubt 

 that the quadritubercular form is a comparatively recent acquisition. 



In conclusion, I would refer both these authors to the types of molar 

 teeth found among the Mesozoic Mammalia. It was while studying the 

 rich collection in the British Museum that I became convinced of the 

 force and universal application of the tritubercular theory proposed by 

 Cope. 



AMERICAN MUSEUM OF NATURAL HISTORY, 

 NEW YORK, July 18th, 1892. 



2. 



THE HISTORY OF THE CUSPS OF THE HUMAN MOLAK TEETH. 



Address before the New York Institute of Stomatology, April 19th, 1895. 

 [Reprinted, under the title given above, from the International Dental Journal. July, 1895.] 



I wish to congratulate the members present upon the formation of 

 this Institute of Stomatology. It seems to me to mark one of the 

 stages in the remarkable specialization of human knowledge when, at 

 the present time, it is proposed to devote the work of an entire 

 society to the scientific study of the mouth parts, as I understand 

 your object to be ; and I also gather from the fact that you have 

 asked me, as a comparative anatomist, to deliver an address this 

 evening, that you look at the subject in two ways, from the stand- 

 point of applied or practical science and from the stand-point of theory. 

 It is on the theoretical side that I should like to bring before you 

 this evening the history or origin of the cusps of the human molar 

 teeth. 



We take up this skull of an Eskimo, and you will observe that 

 the teeth (Fig. 40, No. 11) are slightly worn, and that the molars 



