V iii THE STRUCTURE OF MAX 



hitherto discovered. During the passage of these pages through 

 the press, my friend and colleague, Mr. E. T. Newton, has de- 

 scribed 1 from the Thames Terrace-Gravel, at Galley Hill, in 

 Kent, some remains of a human skeleton which there is good 

 reason for believing to belong to the Palaeolithic Age, and to be 

 perhaps slightly older than the Spy example. The Belgian 

 remains were found in caves, those from Galley Hill were em- 

 bedded in a Pleistocene river deposit ; and it is a significant fact 

 that the skull of the latter gives a cephalic breadth index of 

 but 64. 



The posterior molars or " wisdom teeth " of modern Man are 

 exceedingly variable . structures (cf. text, p. 159). Even when 

 most fully developed, their crowns are as a rule less extensive 

 than those of the teeth in front of them. In remains from 

 reputed Palaeolithic deposits hitherto described, in which jaws 

 and teeth have been preserved, the crowns of the " wisdom teeth " 

 are as large as, if not a trifle larger than those of the other 

 molars in front of them. This greater development of the last 

 molar is characteristic of the oldest known human jaws, but is 

 only very rarely met with in those of recent Man. In its most 

 expanded condition the crown of the wisdom tooth of both 

 recent and fossil Man may be beset by numerous tubercles, its 

 posterior and external cusps being subdivided and replaced by 

 a series of smaller ones. The same variation has been observed 

 among the Anthropoid Apes. This is an intensely interesting 

 fact, as it approximates the molar of Man and the higher Apes 

 with that of the multitubercular type, occurring among the 

 oldest fossil and in the young of one of the two lowest living 

 Mammals (e.g. Ornithorhynchus). Concerning the general question 

 of mammalian tooth-genesis, choice to-day lies between the theory 

 of " Trituberculism," originated by Kiitimeyer and Cope, and 

 staunchly upheld by the American Palaeontologists, and that of 

 "Polybuny" or " Multituberculism " founded and recently de- 

 veloped by Forsyth-Major. The advocates of the former would 

 derive the various types of mammalian cheek-teeth from a 



1 Paper read before the Geological Society, London, 22nd May 1895. An 

 admirable critical review of the subject of Fossil Man, by Dr. A. Keith, giving full 

 references to original treatises up to the time of Newton's important work, will 

 be found in Science Progress for July ] 895. 



