368 THE SKIN AND THE SENSE-ORGANS. 



According to Pfitzner these cells secrete a substance, which has 



Fig. 229. 



w 



I) 1 



Vertical section through the skin of the back ; after Wiedersheim. 



Co Superficial layer of cntis. Ep Epidermis. 



Col Middle layer of cutis. H Horny layer of epidermis. 



Co2 Deep layer of cutis. P Pigment-cells. 



D Cutaneous glands. W Papillae. 



Dl Ducts of cutaneous glands. 



an important function in connection with the process of casting the 

 skin, which consists in the separation of the upper layer from that 



Fig. 230. 



Fig. 231. 



Surface view of epidermis of Rana temporaria ; Nerve terminations in the branched pigment-cells 



after Eberth. of the cutis ; after Ehrmann. Hartnack, Obj. 



A Epidermal cell. 



B Stoma-cell. I. Pigment ceasing abruptly at junction of 



C Attached cuticle from duct of gland. nerve. 



It Protoplasm and nucleus of stoma-cell. II. Pigment gradually ceasing along the nerve. 



below brings abo\it a complete shedding of the skin (Wiedersheim). 



