74 FLORIDA GEOLOGICAL SURVEY-EIGHTH ANNUAL REPORT. 
ccirincitci; much thicker than in C. serpentina; border not notched; 
upper surface sculptured. 
The ninth peripheral here considered (pi. 6, fig. 8) is 38 mm. 
long and 30 mm. wide at the ends; 27 mm. wide at the socket for 
the costal. It belonged to an individual whose carapace was close 
to 12 inches in length. 
Inasmuch as we have at hand the hinder end of the eighth 
peripheral referred to C. laticarinata and the front end of the ninth 
of C. sculpta it is easy to compare them. The two bones are nearly 
of the same length, that of the first mentioned species being 44 
mm. The thickness of the bone at the hinder end in C. laticarinata 
is 11 mm.; in C. sculpta 9 mm. The ninth marginal scute, on the 
hinder end of the eighth peripheral of C. laticarinata, has a width 
of 28 mm.; on the front end of the ninth peripheral of C. sculpta, 
the width is only 20 mm. On the lower side of the eighth peripheral 
of C. laticarinata the surface which was originally covered with 
horny material is 23 mm. wide; on the front end of the ninth of 
C. sculpta only about 12 mm. The upper surface of the peripheral 
of C. laticarinata is smooth; in C. sculpta it is varied by the pres¬ 
ence of pits and grooves. By its inner border this bone was joined 
by a jagged suture with the sixth and seventh costal bones. This 
bone presents no indication whatever of a notch in its free border. 
A left seventh peripheral from Vero with the number 7090 
(pi. 6, fig. 9) has a length of 33 mm. and a thickness of 10 mm. 
at each end. The inner border is injured, so that the width cannot 
be determined; it was at least 23 mm. The rear of the seventh 
marginal is 11.5 mm. high. Differences in form between this bone 
and the eighth peripheral described above, differences seen espe¬ 
cially on the underside, may be due to differences in age and size; 
but the upper surface of the seventh is strongly pitted and ridged; 
and it is, therefore, referred to C. sculpta. 
The three fragments of costals can be only provisionally as¬ 
signed. One, No. 7091, the upper third of apparently the right 
fourth costal (pi. 4, fig. 7) has a width of 29 mm. I here is 
present a lateral carina running along outside of the vertebral 
scutes, as in C. serpentina. Mesiad of this is a longitudinal de¬ 
pression more marked than in the existing species. Descending 
behind the sulcus between the second and third costal scutes is a 
broad groove which is only faintly indicated in C. serpentina. The 
