376 AMERICAN TESTUDINATA. Part II. 



skeleton from Cape Sable, all of which I shall describe on another occasion. It 

 is possible that this Turtle is the American representative of the Halichelys nigra 

 of Fitzinger, founded upon the Caretta nigra, Ilirr., which is said to occur on 

 the Atlantic coasts of Europe and Africa. As to the genus Cimochelys, proposed 

 by Owen for Chelonia Benstedi, and afterwards abandoned by himself as a generic 

 type, I am inclined to consider it as Avell founded, though, judging from its form, 

 I am not satisfied that it is a true Chelonioid.^ 



In the genera of this family the whole body is covered with a scaly epi- 

 dermis, and on the head where the skin fits close to the bones, on the shield, 

 and on parts of the wings, the scales are large and distinct. On the upper 

 surface of the head there is one large median scale, surrounded by a row of 

 more or less numerous smaller scales, one or two pairs of which reach down from 

 that row to the nose. A field of large scales covers the cheek. A thick, horny 

 sheath always envelops the alveolar surface of each jaw, the wide space of the 

 front part of the roof of the mouth before and on each side of the opening 

 of the passage from the nasal cavity, and the whole upper surface of the lower 

 jaw aljout the symphysis. Just back of the bill on the lower jaw there is a 

 large scale. On the ends and front edges of the limbs, the scales are large. 

 On the inner edge of the wing there is a row of four or five scales, which 

 seem to correspond to the quill feathers of a bird's wing. The scales on the 

 shield are arranged in regular rows, namely, one row all round the outer edge, 

 one row along the median line above, one row on each side of the latter covering 

 the costals, and four rows on the plastron, one just within the marginal row, 

 and another between this last and the median line, on each side. The marginal 

 row terminates, in front, by an odd scale, and behind, by the meeting of a pair. 

 The number of pairs in this row varies somewhat in different specimens; in 

 Chelonia and Eretmochelys there are, however, usually twelve pairs; in Thalas- 

 sochelys there are thirteen. The odd scale at the front end of this row is very 

 broad, several times broader than long. The number in the row over the median 

 line is four ; in the row on each side of this last, four or five, four in Chelonia 

 and Eretmochelys, and five in Thalassochelys. The outside rows of the plastron 

 consist each of four, the inner, two rows of six scales each ; besides, there are 

 some large scales under the hind part of the shoulders, and sometimes one or 

 more are interposed at either end of the median line of the plastron. 



K we now consider the American genera separately, they may be characterized 

 in the following manner. 



'D 



1 Compare my remarks about this species, p. 339, note 3, at the close of the note. 



