vill THE STRUCTURE OF MAN 
hitherto discovered. During the passage of these pages through 
the press, my friend and colleague, Mr. E. T. Newton, has de- 
scribed’ 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 Paleolithic 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 Paleolithic 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 hes between the theory 
of “Trituberculism,’ originated by Riitimeyer and Cope, and — 
staunchly upheld by the American Paleontologists, 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 1895. 
