The Zoologist— June, 1869. 1711 



colours than usual, and with the surface moist and very smooth, I had 

 supposed that this appearance might have depended upon the stale of 

 the animal's health, or the influence of some peculiarity in one or other 

 of its functions : on watching carefully, however, I one day observed 

 a large one, the skin of which was particularly dry and dull in its 

 colours, with a bright streak down the mesial line of the back : and 

 on examining further I discovered a corresponding line along the 

 belly : this proved to arise from an entire slit in the old cuticle, which 

 exposed to view the new and brighter skin undernealh. Finding, 

 therefore, what was about to happen, I watched the whole detail of 

 this curious process. I soon observed that the two halves of the skin, 

 thus completely divided, continued to recede further and further from 

 the centre, and become folded and rugose; and after a short space, by 

 means of the continued twitching of the animal's body, it was brought 

 down in folds on the sides. The hinder leg, first on one side and 

 then on the other, was brought forward under the arm, which was 

 pressed down upon it : and on the hinder limb being withdrawn, its 

 cuticle was left inverted under the arm, and that of the anterior 

 extremity was now loosened, and at length drawn off by the assistance 

 of the mouth. The whole cuticle was thus detached, and was now 

 pushed by the two hands into the mouth in a little ball, and swallowed 

 at a single gu\p."— Bell's 'British Reptiles,' p. 120 of the Second 

 Edition. 



This phenomenon has also been observed, as before stated, in the 

 natterjack, frog, salamander, and both the common species of newt, 

 so that we must conclude it is a law throughout the Metamorphotic 

 Reptiles. 



A third and most interesting distinction between the Immutable 

 and Metamorphotic Reptiles is to be found in the existence of a 

 highly poisonous viscid fluid which exudes through pores in the skin : 

 this fluid is secreted by follicular glands seated under the skin almost 

 over the whole of the dorsal area, and is emitted at the will of the 

 animal ; but whether from fear or anger it is impossible to say. I 

 find some very imperfect observations on the properties of this secre- 

 tion in the 'Philosophical Transactions' for 1826, by Dr. John Davy, 

 who concludes that it is innocuous : this assumption, however is 

 erroneous. The earliest tangible experiments with this poison were 

 made by two French philosophers, Gratiolet and S. Cloez, who by- 

 inoculating various animals with the cutaneous fluid of toads and 

 salamanders, have demonstrated that it is endowed with well-marked 



