THE GEOGliAPIirC TURTLES. 75 
Tlir sutures between dorsul plates are always exposed, 
and the inil)rieation referred to is a slight projeetion of the 
dorsal tubercle posteriorly seen in some young examples. 
In adults this tubercle does not commonly extend beyond 
the posterior outline, and the posterior extremity of the 
tubercle is in some examples as far in front of the poste- 
rior margin of its [)late as it extends in others I)eyond it. 
In addition to which the tubercles are quite evident in M. 
r/eo(/ra2)Incus and in young examples may show a tendency 
to i)roject beyond the posterior edge of the phites. The 
statement that the markings of M. lesueuvi are less dis- 
tinct was probably made after an examination of young ex- 
amples. Of the two the adult M. lesueuri is generally 
most brightly marked. Exceptions to this may occur, but 
I think not many. Adult M. geograpJticus are certainly 
very obscurely marked, though still maintaining much of 
the original pattern. 
Similar objections may be urged against the account of 
the geographic turtles in Dr. D. S. Jordan's Manual of 
Vertebrates. 
The jaw is described as having a spoon -shaped dilation, 
and the dorsal plates are said to be imbricated in M. le- 
sueuri. The descriptions are good so far as they go, but 
no important diiFerence between the species is mentioned. 
To illustrate, I will run briefly over the first one given, 
that of M. geographicus. It is described as " dark olive 
brown with greenish and yellow streaks and reticulations, 
especially distinct on neck, legs and edges of carapace." 
This will apply equally well to the other species with the 
exception of the reference to the greenish lines. On large 
examples the lines on the head and neck assume this color, 
and I am not aware that they ever do so in M. lesueuri. 
The plastron is described as " yellowish." This will 
serve just as well for M. lesueuri, notAvithstanding that 
