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THE POPULAR SCIENCE MONTHLY. 



obvious to the touch, and this is true with those found in hot as well 

 as in temperate climates, and adds greatly to their repulsiveness. 



Fig. 1. Of serpents, their general form and 



structure are the same. Their bodies are 

 rounded and elongated, and covered with 

 a scaly skin. The vertebral column is 

 continuous with the length of the body, 

 and is divided into joints from 200 to 

 400 in number, but in the large pythons 

 (Fig. 1), as stated by Dr. Carpenter, 

 422 vertebral joints have been counted. 

 To about 360, or \ of these, were at- 

 tached pairs of movable ribs. A rat- 

 tlesnake, with 194 vertebras, had 168 

 pairs of ribs. The vertebra? of the ser- 

 pent are united by a most perfect ball- 

 and-socket joint, and the ribs are joined 

 to the vertebras in a similar manner. 

 These, held and worked by complete 

 muscular adjustment, give to several 

 their wonderful flexibility, strength, and 

 crushing power. 



The well-known boa -constrictor, 

 and the aboma, or ringed boa of South 

 America (Fig. 2), are illustrations of 

 this class of serpents, the term con- 

 strictor being given from their power 

 to close upon and compress whatever 

 is within their folds. 



The structure of the backbone of a 

 serpent has direct relation to its loco- 

 motion, for it is without limbs, and rudi- 

 ments of pelvic bones are found only in 

 the boas, pythons, and a few other spe- 

 cies. But, where the type shades off 

 into allied reptilian forms, the rudi- 

 mental limbs are developed and promi- 

 nent. 



We read that the curse pronounced 

 upon the serpent was, " upon thy belly 

 thou shalt go," and the inference seems 

 to be that, previous to that time, its 

 mode of progression was not upon its 

 belly. This would imply a great ana- 

 tomical change in the structure of the creature at the time in ques- 

 tion, a change which, so far as we are aware, is not proved by paleon- 



Port Natal Eock-Snake, or Python. 



