No. 1605. ON THREE SPECIES OF SEA-TURTLES—HA Y. 197 
Besides his type, Eschscholtz had a larger specimen, which differed 
in many respects from the type. Its head was 6 inches long and 5% 
inches wide, the greatest width being just behind the eyes. The 
width, then, was 96 per cent of the length. In these measurements 
the length of the head is taken to, or nearly to, the end of the supra- 
occipital process. The skull of C. remivaga, being larger than the one 
just described, ought, if it belonged to the same species, to have a 
width of at least 150 mm., instead of about 125 mm. 
A consideration of Eschscholtz’s descriptions leads to the conclu- 
sion that either his specimens belonged to two distinct species or that 
during growth there occurs a remarkable increase in the width. The 
skull of a specimen of C. caretta, No. 29204, has a length, from the 
snout to the supraocciptal process, of 155 mm.; the greatest width 
is 117 mm., 75 per cent of the length. An aged specimen, No. 29234, 
from Swan Island, Caribbean Sea, has the length of the skull, as 
measured above, 8317 mm.; the width, 260. The percentage is there- 
fore 82. The increase in the width during growth is then far less 
than in the supposed specimen of ZL. olivacea. 
NY DESCRIPTION OF PLATHRS. 
JPEN WIL 
Colpochelys kempi, No. 29823, X¢#. 
Fie. 1. Carapace. 
2. Plastron. 
nA WIE 
Caretta caretta, No. 29013, X23. 
Hie. 1. Skull seen from above. 
Colpochelys kempi, No. 29323, X 2. 
bt 
. Skull seen from above. 
. Horny sheath of lower jaw. 
. Horny sheath of upper jaw. 
He OO 
wa Valor 
Caretta caretta, No. 29013, <3. 
HIG. 1. Skull seen from below. 
Colpochelys kempi, No. 29823, <8. 
2. Skull seen from below. 
Caretta caretta, No. 290138, 2. 
3. Horny sheath of lower jaw. 
4. Horny sheath of upper jaw. 
