74 THE DIFFEKENCES BETWEEN 
there is a spot on each side of the head Ijchind the eye and, 
very generally, at least, only one. 
The statements with reference to the keel of the cara- 
pace are right for adults. Excepting reference made to 
the keels there is nothing in the description which follows 
that will enable anyone to distinguish the species. 
The statement concerning a yellow spot before and an- 
other behind the ear in M. lesueuri was, I suspect, draw^n 
from De Kay's figure. 
The synopsis of reptilia by Messrs. Davis and E,ice 
(Bull., Ill, 111. State Lab. Nat. Hist., 1883) introduces the 
expression " spoon-shaped dilation of the extremity of the 
lower jaw" as a character separating the two inland spe- 
cies from the east coast turtle, M. palustris. The ex- 
pression does not seem to me to lit either of the fresh 
water species closely, and I have never known a student 
using a synopsis or description in which the expression was 
employed to place either of the turtles in the genus Mala- 
coclemmys. The mandible of adult M. geogrcifphicufi is 
greatly expanded, not especially at the tip, but as a whole ; 
and in this respect it is approached very much more closely 
by the east coast species than by M. lesueuri. In the last- 
named species the mandible is not noticeably expanded 
and certainly is no more spoon-shaped than the mandible 
of species of Pseudemys. If the expression was to have 
been used at all, it should have been for the purpose of 
separating M. geograpJiicus and M. ^jft/w-s/j'/s on the one 
hand from M. lesueuri on the other. The two foi'mer are 
not so closely related as are the two inland species, but so 
far as this one character is concerned are certainly more 
alike. The statement that the dorsal plates of M. lesueuri 
are imbricated while those of M. ffeograpJiicus are not, 
is not strictly true. The plates are not imbricated in the 
proper sense of the word in either species. 
