SERPENTS. 63 



occiput but slightly enlarged. Their most distinguishing character is a 

 longitudinal range of scales on the back, which is strongly carinate, broader 

 than the lateral ones, as in Dipsas. These serpents are all from India, 

 where they are termed Rock Snakes. One species attains a length of 

 seven or eight feet*. 



HvDRUsf , Schn., partim. — Hydrophis and Pelamis, Daud. 



Have the posterior part of the body and tail strongly compressed, and 

 much raised vertically; a circumstance which, by enabling them to swim, 

 renders them aquatic. They are very common in certain latitudes of the 

 Indian Ocean. On account of their (nearly all) small scales, Linnaeus 

 classed such of them as he knew with the Anguines. Daudin has subdi- 

 vided them as follows : 



Hydrophis j. 



Have a range of scales on the belly somewhat larger than the others, as 

 in Tortrix; head small, not inflated, obtuse, and furnished with large 

 plates. Several species have been found in the salt-water canals of Ben- 

 gal, and others in the Indian Ocean §. 



Pelamis. 



The Pelamides have large plates on the head, but their occiput is in- 

 flated on account of the length of the pedicles of the lower jaw, which is 

 extremely dilatable ; all the scales on the body are equal, small, and ar- 

 ranged in compact hexagons. 



The species most known, Anguis platurus, L.; Hydrus bicolor, 

 Schn.; Seb. II, lxxvii, 2; Russel, xli, is black above, yellow be- 

 neath. Although excessively venomous, it is eaten at Otaheite. 



To these two subgenera I have added, 



Chersydrus ||, Cuv. 



Whose body and head are covered with small scales. Such is 



Acrochordus fasciatus, Shaw; the Oular-limpe, Rept. pi. exxx. 

 A very venomous serpent, found on the bottom of rivers in Java^T. 



* The Bongare a anneaux, Daud. V, Ixv, Boa fasciata, Schn., copied from Russel, 

 III. — Add, the Bong, bleu, Boa. lineala, Sh. Russ. I. 



f Hydrus, the Greek name of an aquatic serpent, perhaps of our common Coluher; 

 but the Hydrus marinus of .Elian is precisely of this genus. 



% Hydrophis, Water Serpent. 



§ See the Hydrophis of Russel, Serp. Corom. pi. xliv, and part II, pl.vi — x. Add, 

 the H. cur tins, Sh., the H. spiralis, Id. pi. 125; — the Leyoselasme and the Disteyre, 

 Lacep. An. Mus. IV, also belong to the subgenus Hydrophis; I even think the latter 

 is the Hydrus major, Sh. pi. 124. They also are Serpents of the Indian Ocean, ve- 

 nomous, and possessed of sevei'al maxillary teeth. 



N. B. I cannot agree with M. Fitzinger as to the harmlessness of the Pelamides 

 and the Distcyrcs ; on the contrary, I have fully ascertained their poison gland and 

 fangs to be organized like those of a Hydra or a Bungarus. As to the Aispysure, 

 Lacep. An. Mus. IV, I have not been able to procure it. 



|| Chersudros, the Greek name of the Col. matrix. 



Tf The Hydrus granulatus, Schn., must be closely allied to it. 



N. B. The II. caspius, enhydris, rkynchops, piscator and palustris, Schn.. are mere 

 common Vipers and Colubers. His Hydrus colubrinus is the Banded Platurus. 



