168 
ox THE PHYSIOGXOMY OF REEPEXTS. 
several rows of dark spots ; below yellow, with square 
black spots. Spain produces a pretty variety, with yellow 
dorsal rays. S. 186 + 68. 
18. Tropidonotus scaber. This is one of the most 
curious serpents, in this respect, that the extremities of 
the anterior spinous apophyses of the vertebrae of the 
neck, in the shape of teeth, penetrate the tunics of the 
oesophagus. The lachrymal gland, of an extraordinary 
size, extends to the angle of the mouth. In other re- 
spects, this serpent does not differ in any remarkable de- 
gree from the other Tropidonoti. Its head is very thick, 
short, clumsy, and covered with plates of a short form ; 
the frenal is wanting. The scales, disposed in 25 rows, 
are surmounted by a carina more distinct than usual. 
The trunk is elongated, and the tail short. S. 200 + 45. 
Teeth small, and of equal length. Comes from the 
Cape. 
19. Tropidonotus mortuaries. Head elongated ; 
nostrils and eyes very small, and almost vertical; ante- 
rior frontal plates and superciliaries small; several an- 
terior oculars ; 23 rows of scales, surmounted by a very 
strong carina. Colour almost the same as in the Tr. 
quicunciatus, but more numerous. It forms the passage 
to the genus Homalopsis. Comes from Bengal. PI. 137 
+ 70. 
HOMALOPSIS. 
This is the second and last genus of Fresh- Water Ser- 
pents, and merits, in all respeets, that designation. They 
have forms generally clumsy, and massive, and their head 
has a physiognomy wholly peculiar, although this organ 
has an organization very different according to the spe- 
cies ; it is very thick ; has a short and rounded muzzle, 
is covered by scaly plates, usually very numerous, and 
more or less irregular in shape. The peculiar physiog- 
nomy of the Homalopsis is due, in a great measure, to its 
small eyes, more or less vertical, and to the nostrils di- 
rected upwards, and in the form of a crescent, which 
are so near together, that we usually find but a single 
