ORGANS OF DIGESTION. 391 



and the great anterior maxillary fangs of the noxious species 

 are perforated and grooved on their fore part, to transmit the 

 secretion of the poison gland. The scaly lips, and long, 

 smooth, filiform, sheathed, bifurcated tongue, employed as an 

 organ of touch, are li ttle adapted to give the serpents acute 

 feelings, from their food, which passes through their capa- 

 cious dilatable mouth and oesophagus undivided. The sali- 

 vary glands vary much in their development in different 

 species, but the sublingual is always present, and two large 

 superior and inferior labial glands send their secretions through 

 numerous ducts. The large poison gland, (Fig. 74. .), the 

 analogue of the parotid, below and behind the orbit on each 

 side, is confined to the noxious species : it contains a wide 

 cavity, it is embraced by muscular fibres, and sends its long 

 duct to the perforated base of the poison fang, (Fig. 74. b.) 



The lengthened oesophagus, like the buccal cavity and the 

 stomach, is susceptible of great distention, and in its col- 

 lapsed state is longitudinally plicated ; its thin elastic parietes 

 are lubricated by the copious secretion of innumerable mu- 

 ciparous follicles, and it passes insensibly into the long, 

 straight, and capacious cavity of the stomach, which can be 

 distended with prey to many times the ordinary width of the 

 trunk. The cardiac portion of the stomach is thin, membra- 

 nous, longitudinally plicated, rarely presenting a sudden en- 

 largement or a ccecal portion, and the posterior part of the 

 stomach acquires thick smooth muscular parietes, and tapers 

 to a narrow pyloric orifice, provided with a distinct internal 

 valve and sphincter bands. Beyond the pyloric valve, which 

 is seldom wanting, the duodenum, which presents a villous 

 surface, receives the ducts from the liver, and the separate 

 lobes of the pancreas, and the close narrow convolutions of 

 the small intestine are compactly united together for protec- 

 tion, in a distinct tubular peritoneal sheath, to the com- 

 mencement of the short, straight dilated colon, where there 

 is commonly a circular projecting valve and sometimes a 

 small coecum. The short, straight, and wide colon ends in 

 the cloaca, which receives the terminations of the two ureters, 

 there being no urinary bladder, and of the two oviducts, or 

 the two spermatic ducts ; the single or divided male organ 

 likewise passes out through the cloaca, as in other oviparous 



