78 Journal of the Mitchell Society. [ June 
Holbr, and P. labyrinthica C. Dumeril, but how many species 
it really contains I don’t know, as individual variation in at 
least one species seems quite wide and obliterates the distinct- 
ive features ascribed, to most of the others. 
According- to Dr. Baur ( loco cito') these species are charac- 
terized as follows: 
Concinna by its broad and low shell and its small head. 
Hieroglyjhica by its elongated, narrow shell and its head, 
which is still smaller; the yellow stripes and dots on the head 
are also very much more expressed than in concinna. 
Labyrinthica shows the coloration of head and neck of 
hieroglyfihica, but the head is larger and the shell more as in 
mobiliensis , but by far not so large. 
Mobiliensis has the head like concinna , but larger, the shell 
very much more arched especially in front, the animal 
much larger than in concinna , the upper shell reaching a 
length of 385 over the curve. 
Floridanus is at once distinguished by its oval form and 
the great elevation of the carapace and its color. The cara- 
pace has a very dark brown color with numerous irregular 
lines of yellow. The marginals are dark brown and have 
only one vertical, median yellow line, and are without 
the yellow concentric lines so characteristic of concinna and 
mobiliensis. The carapace is much more arched than in mob- 
iliensis and nearly forms a half circle. The skull is also 
larger than in this species and the jaws are not serrated (sic), j 
The characters quoted above, except those for jloridanus , 
all fall within the range of individual variation of Raleigh 
specimens of concinna , and hence until I am able to examine 
specimens of the others, I cannot help feeling doubtful of their 
validity. 
Raleigh specimens of concinna present the following char- 
acteristics: The carapace is marked with a variegated pattern 
