pared specimen of unknown origin, Cat. No. 36085, U.S.N.M., with 
carapace 260 mm. long; (7)-a carapace and plastron of medium size 
at the American Musuem of Natural History, New York. There is 
no doubt. that all these specimens were secured somewhere along the 
eastern or southern coasts of the United States. 
A result of the writer’s investigations is the conviction that exter- 
nally this species resembles closely the loggerhead, while it is very 
different in its osteology. 
It seems doubtful whether any of the external characters that have 
been mentioned by Garman and Coker as distinguishing this species 
from the loggerhead are applicable in all cases. The width of the cara- 
pace of the bastard-turtle doubtless is usually greater than that of the 
loggerhead, but there appear to be exceptions. A bastard-turtle may 
have the carapace as wide as it is long, or even wider; but No. 
29699, with carapace 240 mm. long, has the width only 92% of this; 
while the loggerhead, No. 290138, with carapace 855 mm. long, has 
the width 94% of the length. 
Tt is true that the Jaws of the bastard-turtle are arched outward, 
or swollen in the larger specimens, while those of the loggerhead are 
straight ; but these differences are hardly to be observed in the smaller 
individuals. While the upper jaw of the bastard-turtle 1s usually 
more hooked than that of the loggerhead, this appears not always to 
be the case, as shown by the specimen of the former from Atlantic 
City and by the horny upper beak of No. 29013, a loggerhead. In the 
former the cutting-edge of the jaw is very little excavated on each 
side behind the tip, so that this descends little below the rest of the 
border; in the latter specimen the border is considerably excavated. 
Plate VIII, fig. 4, represents the buccal surface of the horny sheath of 
the upper jaw of the specimen last mentioned. It will be seen that the 
outline of the front is broad and rounded. Fig. 4, Plate VII, shows 
the sheath of the upper jaw of the large specimen of the bastard- 
turtle, No. 29323. In this the tip of the snout is more contracted from 
side to side and a sort of keel descends along the midline. In younger 
specimens of the two species these differences are less obvious. 
The size of the anterior and posterior humps is subject almost cer- 
tainly to great variations in the loggerhead. The horny ridges in 
the roof of the mouth of well-developed specimens of the two species 
appear to be greatly different. In the large individual of the bas- 
tard-turtle, No. 29323 (Plate VII, fig. 4, there is seen to be a promi- 
nent ridge on each side, and this runs nearly parallel with the cut- 
ting-edge of the jaw. The ridges converge forward, but each dimin- 
ishes in height as it approaches the other, so that there is a deep 
notch between them. Each ridge diminishes in height also back- 
ward. Each is really a long-based horny tooth. These teeth show 
