CLASSIFICATION OF REPTILES.
Serpents admit of a very natural distribution into two sections, according as the scales on the belly are simi lar or dissimilar to those on the back. Other charac ters, correlative with these, intimate the propriety of the arrangement.
Serpents with the Ventral and Dorsal Scales The serpents of this division which are destitute of ventral shields have the lower jaws intimately united, and supported at the base by two ossa quadrata, which are articulated immediately to the cranium. The up per maxillary bones are united to the cranium and to the intermaxillaries. This arrangement limits the pw.v er of gaping or of swallowing objects larger than the ordinary aperture of the mouth. The body is nearly of equal thickness at both extremities. Progressive mo tion is chielly accomplished by unbending the arches into which the body is successively thrown. The body can advance or retreat by either extremity, with nearly equal readiness. The eyes are so small, that with many they have passed unobserved.
Serpents with a 7'hird Eyelid.
In the animals of this group the teeth are small and nearly of equal size. The tongue is notched in a cres cent form. The ribs arc more or less united to supply the place of a sternum. When irritated, the body is thrown by thc muscles into a very rigid state, in which condition it breaks into fragments by the slightest stroke. None of the species are considered venomous. The condition of the rudiments of some of these organs, possessed by the Saurian reptiles, which may here be detected, justify the subdivision of the three genera here contemplated.
Traces of scapular and clavicular bones occur under the skin. There is likewise a minute sternum and an imperfect pelvis. Though the rudiments of the extre mities can be detected within the skin, there are no ves tiges of legs or feet on thc outside.
The tympanum is externally visible. The maxillary teeth are conical, and besides these there are two groups on the palate.
Sp, t. Ophisaurus ventralis. This is the Anguis ven tralis of Linnxus. It inhabits the United States. The tail is longer than the body, to which it is joined by a hollow circular furrow. On account of its brittleness, it is termed by Catesby the glass snake.
The tympanum is concealed. No palatine teeth. The maxillary teeth are compressed and recurved.
Species I. finguis fragilis. Blind-worm. This spe cies is ovoviviparous. It feeds on beetles, mice, and frogs. It resides in holes near woods and heaps of rub bi,h. It varies considerably in its colour markings. In its young state it hasrbeen regarded as a distinct spe cies, under the title dinguis crix, or Aberdeen snake.
No vestiges internally of pelvis, scapula, clavicle, nor sternum ; the anterior ribs, however,are united by inter vening cartilaginous productions, which serve instead of a sternum.
The teeth are conical. There is thc ludiment of a sc.. cant! lobe of the lungs.
Sp. I. Arontias meleagris--the Anguis mcleagris of Linnxus. It is a native of India. In the distribution of the colours on the body, it resembles the Guinea-fowl Hence the oi igin of its trivial name.