INTEGUMENT. 



19 



This richness in glands is a characteristic of the 

 skin of Amphibia, and to it they owe their moist and slippery 

 nature. Frequently, as for instance in Toads, the skin is not 

 smooth, but has a rough, warty appearance, caused by local 

 proliferations of the epidermis. 



Fif;. HA. SKIN OF LARVA OF SALAMANDER (Sdlamandra maculosa). 



Ep, epidermis ; Co, derma ; a, stratum corneum ; b, stratum Malpighii ; LZ, 

 Leydig's cells ; CS, striated border. 



The pigment, accumulated principally in the derma partly 

 diffused, partly enclosed within the cells is under the control of the 

 nervous system, and thus renders a change of colour possible ; 

 and as the colour becomes modified according to the surroundings of 

 the animal, it may serve as a protection. 





FIG. HB. SECTION THROUGH THE SKIN OF ADULT SALAMANDER (S. maculosa). 



Ep, epidermis ; Co, derma, in the richly pigmented (Pi) connective-tissue stroma of 

 which the various sized integumentary glands (A, C, D, D, E) lie embedded ; If 1 , 

 the muscular layer of the glands, lying within the membrana propria (Pr) ; M, 

 the same, seen from the surface ; E, epithelium of glands ; S, secretion of 

 glands: Mm. subcutaneous layer of muscles, through which vessels (G) extend 

 towards the derma. 



Calcifications may also occur in the derma, or, as in Cera- 

 tophrys dorsata, definite bones may be formed. Such bony plates 



C 2 



