LEPTODIRA. 173 
Upperside of the head mottled with brown; a brown temporal band. Lower parts 
yellowish. 
The largest of four specimens is 22 inches long, the tail measuring 54. 
11. Leptodira frenata. 
Sibon frenatum, Cope, Proc. U.S. Nat. Mus. ix. p. 184 (1887). 
Hab. Muxico, Jalapa. 
_ Scales in twenty-three rows. Body rather slender; head very distinct and depressed. 
Loreal nearly square. Preeoculars two, the upper not reaching the vertical; two post- 
oculars. Nine upper labials; eye resting on the fourth and fifth, and separated from 
the third by the small inferior preeocular. Temporals 1+2-+3. Posterior chin-shields 
much longer than anterior. Ventrals 188. 
The coloration is described as follows :—Above black, below white. At distances 
of from six to nine scales, narrow cross-bands of one scale in width rise from the 
abdominal border-colour, and meet or terminate in alternating positions; on or near 
the middle line of the back these bands are more or less grey, sometimes darker in the 
middle. The top of the head is grey, densely mottled with blackish, having a con- 
centric space of light grey between a black spot behind the head-shields and the 
beginning of the black of the superior surfaces. A broad black band passes downwards 
and posteriorly from the eye, and, crossing the angle of the mouth, covers the side of 
the neck and unites with the black of the following regions. 
The typical specimen seems to have been very young, only 12 inches long. 
12. Leptodira rhombifera. (Tab. LIV. fig. C.) 
Leptodira rhombifera, Giinth. Ann. & Mag. N. H. 1872, ix. p. 32. 
flab. GuateMALa, Rio Chisoy near Cubulco (Salvin). 
‘Scales in twenty-five series. Anterior frontals very small ; vertical as long as snout; 
loreal longer than deep. Preocular single, barely reaching the vertical; two post- 
oculars. Hight upper labials, of which the fourth and fifth enter the orbit. 
_Temporals 1+2-++3. Chin-shields rather elongate, equal in length. Body rather 
slender; head broad and depressed. Ventrals 170. 
Brownish. Trunk with about twenty-six large, subrhombic, dark brown spots 
edged with black ; yellowish cross-bands, brightest on the median line, separate these 
rhombic spots from one another. Upper part of the head brown, powdered with 
black. A black stripe with a yellowish margin on each side connects the crown of the 
head with the first rhombic spot. Abdomen yellowish; subcaudals powdered with 
brown. 
One specimen, 23 inches long, the tail measuring 5. 
