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. 



FIG. 11 A. SKIN OF LARVA OF SALAMANDER (Salamandra maculosa). 



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

 Leydig's cells ; OS, 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 varioTis sized integumentary glands (A, C', D, D, E] lie embedded ; M l , 

 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 



