OPHIDIA. 281 



among the Saurians ; a range of pores before the anus ; tlie toctli few, conical, and gro-ning only from 

 the jaw, none from the palate ; and they have only one lung. 



There are three or four species, wliich live on insects, and are found princijially about ant-hills, a circum- 

 stauce which lias induced the opinion that they subsist chiefly upon Ants. They are oviparous. 



The Tvphlops {Ti/ph/ops, Schneider) — 

 Have the body covered with small iml)ricated scales, like tlie Orvcts, with which they were long 

 arranged ; the muzzle prolonged and plated ; the tnngnc ratlier long and forkerl ; the eye reduced to a 

 point, scarcely visible through tlie skin; the anus nearly at the extremity of the body ; and one lung 

 four times as large as the otlier. They are small species, resembling Earth-worms at the first glance, 

 and are found in the hot regions of both continents. 



Some have the head obtuse and even with the body, rcsemliliug packtlu-ead at both ends. Others have the 

 muzzle depressed and obtuse, with scaly plates anteriorly. Some, again, liave the fore-part of the muzzle covered 

 with a sint^le broad plate rather shai-p in front. And there are others in which the muzzle terminates in a Httle 

 conical point, being also totally blind : the posterior extremity of these is enveloped in a bony oval buckler, and 

 they were formerly ranged with the Orvets, on account of their small scales. 



The other tribe, or that of the Serpents properly so called, have a tympanic bone or pedicle to 

 the lower jaw, Avhich is moveable, and nearly always suspended by another bone analogous to the 

 mastoid, VN'hich latter is attached to the skull by muscles and ligaments, that allow it also to be 

 moveable. The branches of this jaw are not united together, and those of the upper are connected by 

 ligaments only to the intermaxillaries ; so that they can open more or less, wdiich imparts to these 

 animals the capaldlity of dilating the mouth, so as to swallow obiects of greater bulk than themselves. 



Their palatal arches partake of this mobility, and arc armed with recurved and poiulcd tcetJi, 

 which is the most marked and constant character of this tribe; their windpipe is very long; the 

 heart phiccil far backward ; and the greater nund)cr have only one great lung, with the vestige of 

 a second. 



They divide into venomous and non-venomous, and the former of these into venomous having 

 several maxillary teeth, and into venomous with isolated fangs. 



In the non-venomous, the branches of the upper jaw are furnished throughout their length, like 

 those of the lower jaw and the palate, with fixed and solid teeth. There are three or four subequal 

 ranges of these teeth in the upper part of the mouth, and two in the lower.* Those among them 

 which have the mastoid bones inclosed within the cranium, the orbit incomplete behind, the tongue 

 short and thick, and which resemble the Doiibk-]\[archeurs in the cylindrical form of their head and 

 body, were formerly classed with the Orvcts, on account of their diminutive scales. 



The Roles {Tortr'ix, Oppel ; Torquatrix, Gray; Ilyuay Hemp.), — 



Are externally distinguished from the Orvets by the range of scales along the belly and beneath tlie 

 tail being rather larger than the others, as also by the extreme shortness of the tail. They have but 

 one lung. All are from America. 



The Uropeltis^ Cuv. {Anilius^ Oken), is an allied new genus, the tail of which, still shorter and obliquely trun 

 cated above, is flat and be^et with little scales at the truncation. Their head is very small ; the muzzle pointed ; 

 they have a range of scales under the tail, a little larger than the rest, and a double range beneath its truncate 

 portion. 



The non-venomous Serpents which, on the contrary, have detached mastoid bones, and the jaws oi 

 which are dilatable, have the occi[mt more or less bulged, and the tongue forked and very extensible. 

 Two principal genera have long been di.^tinguished, — the Boas and the Snakes proper. 



The Boas {Boa, Lin.), — 

 Foi'incrly comprehended all Serpents, venomous or not so, the nnder-part of the body and tail of 

 which is covered with scaly transverse bands, each of a single ;uece, and which have neither spur nor 

 rattle at the tip of the tail. Being very numerous, it is necessary to subdivide them, after abstracting 

 the vruomiius ones. 



* The ccmnum (ipiniun is, tluit nil Serpents destitute of pierced i liat:k-molars of Ailiii;h are verj' t'ri,''^f ^""e reputed to be cx'remcjy 



funcs ill tlic I'lwer part of tlie jaw, are nnn-vciiomous ; but tliis I have venomous in the countries whieh Uiey icihabit ; an opinii>n which i; 



a<imc reason to doubt. All have a niaxilkry j^'IhiuI, often very Inr^c ; coniinned by (he expeiinients of Liilaude and Lescheoauld, M-hii:ii It 



nnd tlic bttck-niubirs frequently exhibit a groove, Mhieli wnubi ?cciii to ■ is liesirabJe shoulii be repealed, 



conduct saline li.]Uor. Tins mueh is certain, lliat various s|,Lcies, the I 



