Des Arc citizen., 1859-06-01
HOW sERPENTs CRAWL WITHOUT
 ..e4t LEGS si-s .ss tf

HOW SERPENTS CRAWL WITHOUT
 8 LEGS
 Although deprived of feet, fins and other obvious members for walking. the serpent glides on the earth, ascends trees, or even directs it's course through the wa ters, with surprising agility. and with graceful evolutions; yet the serpent was |. cursed above every beast of the field and man as if remembering the curse, turns from the reptile with disgust and hor- TOT, or seeks to effect its instant destruc- ton. Let us examine how all this is ef- fected, and first as to the spinal column. The numerous bones or verlebr9 which form this chain, are united together by ball and socket articuations, or, in other words, the round head of each is fitted in- to cupllke cavity in it's predecessor, so that the whole column is a chain of these joints, capable of the utmost mobility com patible with the safety of the spinal cord enclosed within. The articulation can on- | Iy be moved from side to side; and the progress by vertical undulations, as is seen in many old prints of serpenls, IS anato- mical impossible So also 1t IS impossible for the snake to perform the feat which has been ascrlbef to nm when he wishes to go quickly down the hill :; according to an absurd story, he IS said to put his tail in hIs mouth, and roll himself down, being in the form of a hoop. It is just as we'll 10 recollect the fact that snake cannot turn himself dI- rcctly upwards when held by the tail He can wrigge famously from side to side, but certainly not upwards. Hence II fol- lows, that the best way to handle snake IS to hold hlm out al arm's length; m this position he can do no harm.
 But how, It will be asked, does the snake conlrve to get along the ground so fast, ash he has uo perceptble legs or arms to help hhn :? This is managed us iol- lows: To each verlebra -and a large snake has many dozen yertebre -is at lached par of ribs; the small ends of these ribs are not attached 10 sternum, or breasl-bone, as ln man, but to single scutum or scale on the abdomen, by means of slender cartilage and d set of short muscles. It IS on the points ot these ribs, which may be compared to the legs oi a tnllipede, that the snake rests; and they act in progressive order, just like the legs of that creature, each pair bringing ior- ward the plate of sculum to which Il IS at lached. This row of scula may thus be regarded as one long ample foot. Sir E. Hone, in his !" Comparative Anatomy gives an account of the muscles which, arising from the ribs, give motion to the scuta. He observes that the rIb Ill the snake performs two functions the upper half is concerned in respiration, the lower m ocomotIon.
 If snake be allowed quietly to crawl over the hand, the progressive movement of the ribs may be easily distinguished, and also if It be watched while crawling over any raised edge Gas the back of q book, requiring the firm application of two or three scuta in succession ss the body gides over 1t.
 If you pu! snake on bit of plate glass he can get no hold with the scuta, and becomes powerless.
 Snakes are often in the habit of climb ing trees. and we see them represented in engraylngs, particularly in old pictorial Bibles where the serpent is seen temptlng Eve. and in stuffed specimens in muse ums, as coiing their bodies round the branches. in corkscrew-llke folds Now the snake when alive never does this; it supply glides up with the whole body ex- tended in straight llne, clinging by means of the tips of the expanded ribs with the scuta attached. as has been above explained. Mir, Gosse tells us that the black snake in Jamaica will allow the greatest part of its body to hang down in the air and thus remain still while lntle more than the tail maintains it's position by clinging Straight, not splrally and not half around it, but longiludinally along it) to the upper surface of branch; and l. will often pass freely and gracefully from one branch to another at a considerable interval, projecting its head and body with the utmost care across the interval. The motions of snake m a tree are beauti- fully easy and free, and convey the i'm pression that the reptile feels quite at home among the branches. - Buckland's Curl osi,ies of Natural History. ~