Royal Physical Society. 187 



quently had aborted eggs, apparently all yolk. In spring, 

 these inoffensive reptiles became among themselves pug- 

 nacious. Two individuals, in particular, I had frequently 

 occasion to separate from what appeared a death struggle ; 

 and as the violence was, in a sense, exceptional, I considered 

 the causa belli to be sexual. 



8. Feeding, Motions, §fc. — This reptile shuns the light, 

 and is often found in long grass, or under the new laid swath, 

 where food is likely to be found. In seizing its prey some- 

 thing like a display of strategy is made. The object is marked, 

 the animal hovers over its victim, arches its neck, and ulti- 

 mately, though the action seems unnecessary, darts upon it. 

 Whatever is seized is gorged, and apparently all but impos- 

 sible masses are swallowed. I have seen — besides slugs, which 

 it seems to prefer, and worms which it feeds on readily — very 

 small frogs and toads, and also caterpillars, to which it was 

 restricted, taken ; and I have good grounds for believing that 

 its own young are not rejected. The manner of seizing its 

 prey would suggest that it has to deal in a state of liberty 

 with animals more active than the snail or worm. The gorg- 

 ing process is slow but certain ; the snail being caught, the 

 slow-worm rests for a considerable time, when a sort of con- 

 vulsive opening and shutting of the jaws take place — a pause 

 and similar efforts occurring at what seems measured intervals, 

 till the object disappears within the jaws. A circumstance 

 which long puzzled my discerning powers, may be worth 

 notice : I remarked that the bulging mouthful, made by a 

 large slug, acquired a singular impulse inwards each time the 

 mouth was opened, and that although the mouth was opened 

 comparatively slowly, an instant snap succeeded, as if to make 

 good the advantage. After careful watching, and a thorough 

 examination of the machinery, I came to the conclusion that 

 the peculiar teeth of fishes and of reptiles were contrived not 

 only as seizing and retaining instruments, but that in the 

 opening of the mouth a necessary mechanical power was exer- 

 cised by the curved teeth, which effected, in animals so con- 

 structed, the needful purpose of advancing, at every such 

 effort, the peculiar nutriment. The animal drinks equally 



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