168 ON THE PHYSIOGNOMY OF SERPENTS. 



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 vertebrse of the 

 neck, in the shape of teeth, penetrate the tunics of the 

 CESophagus. The lachrymal gland, of an extraordinary 

 size, extends to tlie 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. Tlie scales, disposed in 25 rows, 

 are surmounted by a carina more distinct than usual. 

 The trunk is elongated, and the tail short. S. 200 + 46. 

 Teeth small, and of etjual length. Comes from the 

 Cape. 



19. Tropidonotus mortuarius. 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 Homalcpsis. Comes from Bengal. PI. 137 

 + 70. 



HOMALCPSIS. 



This is the second and last genus of Fresh-Water Ser- 

 pents, and merits, in all respects, 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, viiich 

 are so near together, that we usually find but a single 



