TESTUDINATA. 67 
furrows narrow and shallow; the sculpture consisting- of low sharp 
ridges. 
No. 3738 of the collection of the Florida Geological Survey- 
presents the larger part of the right fourth costal of a turtle which 
probably belonged to either Trachemys or Pscudemys. The bone 
is recorded as having come from the top of a stratum of shell marl, 
below an unconformity, about one-eighth of a mile straight east 
of Labelle, on Caloosahatchee river. The marl is thought to be 
probably Pliocene. The bone is much more thoroughly fossilized 
than those bones from the Pleistocene. 
The costal (pi. 7, fig. 1) has lost the distal end. The upper 
end (directed toward the left in the figure) measured along the 
edge of the second vertebral scute, is 36 mm. wide. Where the 
bone joined the third neural it is 10 mm. thick, but at a distance 
of 25 mm. it is reduced to 4 mm. From the position O'f the fur¬ 
row between the third vertebral scute and the second and third 
costal scutes it is seen that the vertebral had only a moderate 
width. 
The sculpture is On the pattern of that of Trachemys scripta, 
but it is more delicate. The ridges are low and sharp. On the 
area of the third costal scute there are four of these in a line 13 
mm. long. On the area of the second costal scute the ridges are 
irregular in direction. 
TRACHEMYS BISORNATA (COPE). 
Plate 7, figs. 2-7. 
A nuchal bone in the collection of the Florida Geological Sur¬ 
vey, finely preserved, is referred to this species. It has the cat¬ 
alogue number 3735 and was found in Pleistocene deposits in Lee 
county. It bears this label: From above the unconformity; about 
1-8 mile by land, east of Labelle, on Caloosahatchee river. 
The nuchal (pi. 7, fig. 2) is larger than that of the Texas 
specimen described and figured by the writer (Fossil Turtles N. 
A., p. 353, pi. LVI, fig. 1), but the proportions are almost exactly 
the same. The length along the midline is 60 mm.; the greatest 
width, 70 mm.; the width in front, 38.5 mm.; the thickness at the 
lateral angles, 16 mm. The front border is acute. The front end 
of the first vertebral scute is 40 mm. wide. The character of the 
ornamentation is shown by the figure. In the one from Texas, 
above referred to, the transverse ridges of the areas of the right 
