288 THE ZOOLOGIST. 



manner that the lowest exposed margin is a little above the 

 surface of the layer. Allusion has been made to the evil 

 of getting the gravel wedged between the frame and canvas in the 

 cold cage ; with glass it is almost as bad, since this gets scratched 

 by the pebbles which the snakes squeeze against it as they pass 

 along, and becomes friable in consequence. A good deep ledge 

 should guard the doorway too, and prevent the stones from 

 tumbling out or blocking its return wben it is opened ; this, 

 however, must be movable, to allow the whole to be cleared out 

 without embarrassmeut when necessary. 



Slowworms are often associated with Common Snakes in an 

 unheated cage, and very pretty little creatures they are, though 

 presenting no points of any especial interest. These ought 

 to have earth or moss in addition, and will not live comfortably 

 upon the gravel, though they have no objection to taking frequent 

 promenades over it. Their requirements may be combined with 

 those of the legitimate occupants, by erecting a little mound 

 of turf in the middle of the cage — upon the floor, not on the 

 gravel— and placing over it a fern-glass, around the lower border 

 of which are pierced a number of smooth round holes, large 

 enough for the slowworms to pass through, but not admitting 

 the snakes. If the dome be not itself sufficiently weighty to 

 prevent the serpents from overturning it, it must be fixed in some 

 way ; the turf-heap may be made ornamental with a fern or other 

 plant, and if plenty of worms and maggots be put in, the slow- 

 worms will feed themselves there at night. A large flower-pot 

 inverted, with the hole at the top blocked up and smaller ones 

 drilled around its base, will answer the same purpose, if the 

 edges of the apertures be filed perfectly smooth, but has not such 

 a pleasing effect and will require extra weight. 



When blankets and rugs are spoken of, coarse horse-cloth 

 may be understood. It is well to avoid the application of such 

 coverings to the snakes bodily, if they can be kept warm with 

 free circulation of air about them ; but when it is called for, we 

 must not forget that blankets do not by themselves make a reptile 

 any hotter. If we clothe ourselves with non-conductive material, 

 our heat increases, because the caloric generated by oxidation, as 

 the vital processes go on, accumulates. A snake's temperature 

 depends entirely on that which it receives from its surroundings, 

 except in one or two rare instances, and then only to an extent 



