^B4 REPTILIA, 



and the ]icad plated to tTic eyes; tlie tail tcrminatod by a spiir. Others have no siibcaudal plates, and the head 

 scaled like the back. Some have the head plated, Mifh double subcaudal plates ; ajul others conjoin to the latter 

 character, excepting; that the extremity of the tail has small scales both above and below, little scales upon the 

 head also. 



Ti-iE Vipers {V'/pora, Daud.), — 

 The greater number of wliicli were confounded by Linnreiis with the Snakes proper, on account of 

 their double subcaudal ])latcs, rei]nire to be separatefl from the latter by reason of their venomous 

 fangs, and grade into oilier Scrpeiits \^iih single or jtnrlly double subcaudal jdatcs, being distinguibheJ 

 from the. Rattlesnakes and Trigonocephalets by the absence of cavities beneath their nostrils. 



Some have only keeled and imbricated scales upon the head, like those of the back ; and others have tiie head 

 covered with small ffranulated scales, [amon^ -which is the Viper or Adder of this country]. Some again [the CV- 

 raHtes] have a pointed bone over each eyebrow, [and are peculiar to Africa]. Others, which are similar in all other 

 respects to the preceding- generally, have three plates a little larger than the scales which surround them upon 

 the middle of the head. There are some Vipers, also, with plates upon the head, like those of the Common Snake. 



Nala — Are Vipers with plated heads, the anterior ribs of which can be dilated and thrown forward, so as to 

 distend this part of the trunk into a disc more or less broad. The most celebrated species is the Cobra di Capella 

 of India, with a spectacle-like mark on the di^k, and Avhich is extremely venomous. The Haje, or Asp, of ligy[it, 

 is another. 



Elaps. — Head plated, and an opposite organization of the body to the Asps ; their jaws even can scarcely widen, 

 on account of the shortness of the tympanic bones, and especially of the mastoids, from which it results that the 

 head is nearly of even size with the Ijinly. as in llie Roles and Aniphisba-rjes. 



Micruriis. >Vagner, has merely the tail ^li(ii"ti.'r\ 



P/rf/'//-//*-, Latreille. — Head also platud, and double plates Ijeneath the tail; but the latter compressed like an 

 oar, v.hich renders them aquatic. 



Finally, we place at the lerniinatlon of the Vipers certain species ^vhicb only differ in having single subcaudal 

 plates, either partly or tliroughout. They are distinguished from the Tisiphones by having no cavities behind 

 the nostrils. 



Some, with entire plates at the base of the tail, compose the Tr'iHcrcnir?'.\; Lacepedc, having large plates on the 

 head, and some of tlie subcaudal ones double, others single. 



Oplocephalus, Cuv. — Have great plates on the bead, and all the subcaudals single. 



Acanihophis, Daud.; Ophrias, Merrem — Plates in front of the skull and of the head, the tail terminated by a 

 hook, and all its plates simple, though sometimes there are double ones at its extremity. 



Echi.s, JMcrrcm. — Small plates on the head, and all the subcaudals single. 



Z,'";?7(7a//rt, Bnignieres. — Head plated; tlie muzzle pointed and prnjpcting-, anterinr half of the tail encircled 

 with entii'e rings, and the postei"ior with little imbricated .sealer buth ab-.i\"e and below. 



Besides these two tribes of Serpents properly so called, which have been longer known, a third has 

 been discovered more recently, the jaws of Avhich are organized and armed nearly as in the noii- 

 venomous kinds, but wdiich have, nevertheless, the first of their maxillary teeth longer than the rest, 

 and pierced for the purpose of conducting venom, as in the genera with isolated fangs, already described. 



These Ser])ents form two genera, distinguished from tho:^c of the (wu allied families, by the scaling 

 of the belly and under-part of the tail. 



T(!E B0XG.\RS {PseiKhjhon, 0])pe!.) — 



Possess, like the Boas, the Rattlesnakes, and thi- Seuids, :>iiiipl(.' plates beneath the belly ami tail. 

 Their head is short, covered with large plates, and the orcipnt but slightly bulged. Their most cliarac- 

 teristic di^itinctinn, however, cnnsists in their \ei y eariiuited back being furuj^-hcd \\\\\\ a longitudinal 

 range of scales, lirortder than the lateral luics, as in the l.iipsas. 



They inhabit the Last Indies, where they are called Roch •Snakes, one of the S[)ecies attaining a length of se\'en 

 or eight feet. 



The Hydras (l/i/drfs, Schneider, in jiart ; Ifi/>J/ojiI//s imhI Pdaniiilcs, Daud.) — 



Have tlic back part of the body and tail very much compressed and raised vertically, which, imparting 

 lu llicm the pnwer nf swimming, renders them aquatic animals. They are very common in certain 

 parts of the liulia)i Seas, [and cxcrssively venomous, feeding on fishes]. Linnaeus ranged those that 

 were known tn him among the rt;-vcls on account e)f the small scales with which they arc wholly 

 covered. Daiidin has subdivided tliem as follows: — 



Iljlflrophi.s. — These have a range of scales a litlle lir[)ader than tlie re^t under the belly, as in the F.rpetons au'l 

 Roles ; the head small, not bulged, obtuse, and covered with large plates. Several species are lonnd in the salt 

 water of Bengal, and others in the Indian ocean. 



Pelcoitides, — ha\e, also, great iihUes on the hi'ail, but their occiput is bulged on account of the length of the 



