OPHIDIA. 283 



Dnimus, Merrem ; Passerita, Gray. — Body as long and slender as in the last, but a small and slender pointed 

 appendage at the tip of the muzzle. 



Dryophis, Fitzinger. — The same long filiform or cord-like body, but no appendage, and the scales of equal size. 



OUijodon, Boie. Small species, with an obtuse, short, and narrow head, and no palatal teeth. 



After all these dismemberments by diflerent authors, there yet remain several which appear to me less worthy 

 of adoption ; being founded on slight differences in the proportions of the head, the thickness of the trunk, &c. : 

 and there is still left a group the most numerous of all in species, that of 



The Snakes, as most restricted, which have no peculiar distinauishing character. Several of these are <bimd in 

 France, [and one only in Britain, the common Ring-necked Snake (C. natrir and I^atrix torquatus), which attains 

 to a yard in length, and feeds on Frogs, Mice, insects, &c.] It is eaten in some provinces of France. The exotic 

 species are innumerable : some are remarkable for the splendour of their colours ; others for the regularity of the 

 distribution of them ; many are quite uniform in their tints ; and a few only attain a very large size. 



The Acrochordus, Hornstedt-^ 

 Are readily distinguished from the rest of this family by the uniformly small scales with which their 

 body is covered both above and below. 



The kno^TO species (A.javensis, Lac; Angids gramdatus, Schneider,) has each of its scales raised into three 

 little crests, resembling, when the skin is very loose, three isolated tubercles. It grows to a large size. Hornstedt 

 has stated that it subsists altogether on fruits, which in an animal of this kind would be very extraordinary. 



The Venomous Serpents par excellence, that have isolated fangs, present a peculiar structure of the 

 organs of manducation. 



Their superior maxillary bones are very small, borne upon a long pedicle, analogous to the outer 

 pterygoid apophysis of the sphenoid, and are also very moveable ; having a pointed tooth affixed to 

 them, which is pierced by a small canal, through which issues a liquid secreted by a large gland 

 beneath the eye. This liquid it is, instilled into the wound inflicted by the tooth, which poisons 

 the bodies of animals, and produces effects more or less deadly, according to the species from 

 which it is derived. The tooth lies down flat in a fold of the gum when the Serpent has no occasion 

 for it, and behind it are several germs designed successively to replace it, in case it should be 

 left in a wound. Naturalists have termed these venomous teeth crochets mobiles [or fangs] , but it is 

 properly the maxillary bone that moves. These Serpents have no other teeth besides the double 

 range upon the palate. 



All the venomous species of which we possess certain information, bring forth their young alive, the 

 eggs hatching within the body of the parent, [though during the act of parturition]. It is thus that 

 their general name of Vipers has arisen, which is a contraction of viviparous. 



Venomous Serpents with isolated fangs, present nearly the same external characters as the pre- 

 ceding ; but the greater number have extremely dilatable jaws, and the tongue very extensile. Their 

 head, which is wide posteriorly, has in general a savage aspect, which to a certain extent announces 

 their ferocity. They form two principal great genera, the Rattle-snakes and the Vipers, of which the 

 second has many subdivisions, around which some alien small ones require to be grouped. 



The Rattle-snakes {Crofalus, Lin.) — 

 Are more celebrated than any other Serpents for the deadliness of their venom. In common with the 

 Boa, they have simple transverse plates beneath the body and tail, but are most obviously distinguished 

 by the rattling instrument which they carry at the tip of the tail, and which is formed of several 

 scaly cornets loosely attached together, that move and rattle whenever the animal shakes or alters the 

 position of its tail. It appears that the number of these cornets increases with age, and that they acquire 

 an additional one at each casting of the skin. Their muzzle is hollowed by a little rounded depression 

 behind each nostril. All the known species are from America. They are so much the more dan- 

 gerous, as the season or climate is hotter ; but their ordinary habits are tranquil and sluggish. They 

 move slowly, and only bite when provoked, or for the purpose of killing their prey. Although they do 

 not chrab trees, they nevertheless feed principally upon Birds, Squirrels, &c., which it was long be- 

 lieved they possessed the faculty of hallucinating or charming, so as to draw them by degrees to enter 

 their throat. It w-ould seem, however, that the fear which their appearance inspires occasions those 

 disordered movements of their prey, which have given rise to the foregoing supposition. 



Most of the species have the head scaled similarly to the back; while others have great plates upon the head. 

 We approximate 



The Trigonocephali of Oppcl {Bothrops,SpiK; Cophias, Merrem); which are distinguished by the absence of 

 the rattle, but accord in their other characters. Some of these have simple subcaudal plates, as in the preceding, 



