REPTILE. 



561 



The number of processes to which ribs are articu- 

 lated vary in the different genera. In some they are 

 as many as two hundred, or even more, and as far as 

 they extend may be considered as the body of the 

 reptile. The vertebrae of the tail are without pro- 

 cesses for the ribs, as there are of course no ribs there. 

 The processes on the dorsal aspect of that member are 

 also more simple and more uniform in their shape than 

 those on the dorsal aspect of the body. They are little 

 else than simple tubercles in all the species, while those 

 on the back are at some distance apart in the crush- 

 ing serpents, and nearer to each other in the poisoning 

 ones. The ribs may be considered as a sort of legs 

 to the reptile, and the plates or shields on the belly 

 as feet ; but before we can explain the action of 

 them, we must say something of the covering of the 

 body. 



The power of action in the muscles of those ani- 

 mals is as wonderful as their structure. They appear 

 to have to bring themselves up to a certain degree 

 of excitement before they can act with their full 

 vigour ; but when they have done this, their starting 

 into vigorous action is without parallel among ani- 

 mals. When one of the more powerful crushing 

 serpents is stimulated by hunger and the sight of 

 prey jointly, its attack is more like a discharge of 

 electricity than any thing else. It does indeed take 

 some time in working itself up to the necessary pitch 

 of excitement ; but the instant that it has done this 

 the victim is awakened in its folds in such a way that 

 one can hardly tell how it is done, even though stand- 

 ing close by. The gripe of the folds is also tremen- 

 dous ; for it has the power of tightening them by crawl- 

 ing along the skin by the action of the ventral plates, 

 and as, in doing this it has as many points of holding 

 as there are plates, it pulls and tightens as a rope 

 would do it' drawn by a powerful engine ; indeed it 

 does more than this, for it draws in every part of its 

 length at the same instant. A dead substance which 

 is thickly set with barbs will work onward in a won- 

 derful manner. One of the barbed beards of barlev 

 will very soon get from the waist to the shoulder of 

 one who is working at that species of grain ; and the 

 operation of felting, in the making of hats or other- 

 wise, and the milling of woollen cloths, are other 

 instances. These are, however, only dead matter, 

 urged on by mechanical force ; while the creeping 

 motion by which the serpent strangles its prey, and 

 even crushes the bones, is a living power which 

 operates at every point where it touches, and there 

 is really nothing in the mechanics of dead matter 

 that can be brought in illustration of it. The power 

 of what seems to be but a small serpent is very great 

 in this way, and can crush to death an animal, around 

 which it appears nothing but a rope of moderate 

 thickness. It does not fasten indiscriminately, espe- 

 cially if the prey is large, but concentrates its coils 

 at that place where their gripe is the most effective 

 for its purpose. It is probable that the ex- 

 ertion of griping the prey to death in the folds, con- 

 duces to the secretion of that slimy matter which 

 so much facilitates the swallowing of an animal many 

 times the diameter of the swallower. But we have 

 already mentioned the extent to which the gape can 

 be dilated ; and there is hardly any limit to the 

 dilatability of the gullet. 



It has sometimes been said that these crushing 

 serpents break the bones of their prey by straining 

 it against a tree ; but it is doubtful whether it would 



NAT. HIST. VOL. III. 



not lose much more than it gained by such a means 

 of assistance. It is in its coiling round and round the 

 body of the prey, and performing the tightening mo- 

 tion by means of the scales, that the vast crushing 

 power of this animal consists ; and if it were to be 

 coiled round any thing else along with the prey, it is 

 easy to understand that its force would thereby be 

 interrupted in the continuity of its action, and conse- 

 quently lessened in its effect. In the case of small 

 prey, this terrible crushing power is not put in requi- 

 sition, the gape is quite enough to make them find 

 their way to the gullet ; and though it is any thing 

 but a pleasing sight, it is certainly a curious one, 

 to see one of these serpents making a mouth for 

 the devouring of a fowl or rabbit, or any other little 

 animal. 



The reverse of this operation is also a powerful 

 one ; though it is momentary, and does not partake 

 of the curious creeping into close folds, which is the 

 grand part of the crushing. The reversal of the twine 

 round is the other motion, in which the whole mus- 

 cles are brought into play, and it is practised bv 

 many serpents whether they crush their prey, poison 

 it with the fangs, or simply swallow it. Generally 

 speaking, the body is coiled up in circular folds on 

 the surface of the ground, with the tail at the circum- 

 ference, and the head at the centre, and elevated 

 above the coils when the animal is alarmed or ex- 

 cited. It does not at once start from the coil, but 

 opens its mouth, glares with its eyes, sends out its 

 pestilent breath, beats the ground with its tail, and 

 ifiakes a noise with its rattle if it happens to have 

 one. After it has worked itself into a sufficient de- 

 gree of excitement, and there is reason to believe 

 that in doing this both the heat and the quantity of 

 breathing are brought up to more than the usual 

 pitch, it makes its spring as if it were an arrow shot 

 with great force from the bow of its own folds. In this 

 it is careful not to throw away its effect, which is a 

 considerable one ; and as it appears instinctively to 

 judge with accuracy both of the direction and the 

 distance, it seldom misses. Of course it depends on 

 the character of the species, in what manner it acts 

 after it has sprung. If it is a crushing serpent, it 

 twines ; if it is a poisonous one, it uses the fangs ; and 

 if it is merely a swallowing one, it darts open-mouthed 

 upon the prey, and gulps it down upon the spot. 

 Serpents of this last description generally prey upon 

 smaller animals in proportion to their own size than 

 the others do ; and it is also highly probable that the 

 poisoning serpents swallow their small prey without 

 making any use of the poison-fangs. 



It now remains to notice the progressive motions 

 of the serpents on their ordinary march, and when 

 they are not under any extraordinary excitement; 

 but in order to do this we must previously notice the 

 covering of the body. 



The skin of serpents consists chiefly of two parts 

 dermis, or skin properly so called, and the epidermis, 

 or cuticle. The dermis is without any callous sur- 

 face, is of considerable thickness and great strength ; 

 firmly connected to the tissue of muscular fibres 

 underneath, and never cast. This skin is very gelati- 

 nous ; and, when properly tanned, that of the larger 

 ones makes remarkably thick, tough, and durable and 

 excellent leather, only the surface of it has a curious 

 appearance from the impressions of the scales. The 

 epidermis is cast every season. The appendages to 

 this skin consist entirely of scales. There are two 

 N N 



