186 
ON THE PHTSIOONOMY OP SEKPENTS. 
4. Hydrophis gracilis. — Habit of the last, but of less 
size, and of a very attenuated form, especially towards the 
neck, which is very slender. Head smaller than in the 
other species, and very narrow ; yellowish, with transverse, 
lozenge-shaped, black spots. This last colour occupies 
all the anterior parts, so that the ground colour only 
appears as narrow bands. Head black, a light spot 
above the eye. S. 355 -f 50. 27 Rows of scales. Gulf 
of Bengal, and Straits of Sunda. 
5. Hydrophis Pelamis. — ^Has small hexagonal scales, 
disposed as a pavement ; form massive ; head much elon- 
gated ; middle line of the abdomen indicated by a suture 
formed by the two last rows of scales, of which we reckon 
47 in all. S. 350 4- 60. Above blackish-brown ; below 
yellow ; tail, and sometimes even the whole body of the 
animal, varied by these two tints. This is the most com- 
mon species ; it is found in all the latitudes inhabited by 
sea-serpents. 
6. Hydrophis Pelamoides. — Form much more short 
and thick than the last, which it approximates by the 
structure of the scales ; but these organs are larger, and 
we only find from 25 to 30 rows. Vestiges of abdominal 
plates, imbedded in the middle suture of the belly. 
Yellowish, with large dorsal spots lozenge- shaped. S. 
136 + 27. Gulf of Bengal, and Seas of China, and the 
Molucca Islands. 
Hydrophis colubrina. — An anomalous species, easily 
recognised by the smooth imbricated scales, covered with 
a corneous epidermis ; by the lateral nostrils ; by the pre- 
sence of 5 occipital plates ; by its abdominal plates, much 
larger than usual. 23 Rows of scales. S. 220 + 38. 
Dark green, marked with large black rings, obsolete in 
the adult. Almost as common as the H. pelamis. In- 
habits the same places. 
The Third and last Family of Venomous Serpents com- 
prehends 
The Venomous Serpents properly so called. 
They have a physiognomy quite peculiar, with some- 
thing hideous in their aspect. We might even say, that 
