566 



INTEGUMENTARY SYSTEM 



represent areas of considerable cornification. Horny outgrowths of the epi- 

 dermis are common in certain species. 



The dermal layer in general is delicate and characterized by the presence 

 of many pigment cells (chromatophores) of various kinds. The scales within 

 the skin of the Gyninophiona are of dermal origin. In frogs, the dermis is 





LAND :#-:'^^(#'"";d. 



MESENCHYME 

 PIGMENT CELL 





DERMAL CHROMATOPHORE - 



E RMIS 



DERMAL MESENCH 





-^^^^ 



EPIDERMAL PIGMENT CELLS 



V V,r--r^ ^ V /- ^ tJPT'"!- _^^ >; ':5?^^^^0UTER COMPACT 1 



PIGMENT CELLS 

 MUCOUS GLAND 



NNER COMPACT LAYER ii^ 

 OF DERMIS ^~3>vf' 



SUBCUTANEOUS LAYER 



:^f /^INTERMEDIATE SPONGY. ,•»/►« XH L \\ 



i-L-y^ J.a LAYER OF DERMIS ^s< ■•"^' \/ \-f'r.> r 1 



^;^^£:^cAPiLLARY |^\Xk.i vjr -'^^/i 



EPIDERMIS 

 EPIDERMAL GLA 



Fig. 267. Developing integument of amphibia. (A after Field: Bull. Mus. Comp. Zool. 

 at Harvard College, 21; F after Dawson: J. Morphol., 34; H and I after Assheton: 

 Quart. J. Micr. Sc, 38; J from Kingsley, 1925: The Vertebrate Skeleton, Blakiston, Phila- 

 delphia, after Sarasins. ) ( A ) Section of skin of frog embryo in neural plate stage. ( B ) 

 Section of skin of 10-mm. frog embryo. (C ) Skin of 34-mm. frog embryo. (D) Skin of 

 Nectiirus embryo, 6 mm. long. (E) Skin of Necturus embryo, 20 mm. long. (F) Struc- 

 ture of mature skin of Necturus. (G) Structure of skin of Rana pipiens of section 

 through head shortly after metamorphosis. (H) Frog embryo, 3 mm. long, showing 

 water streams produced by cilia. (I) Semidiagrammatic figure through suckers of frog 

 embryo, 6 to 7 mm. long. (J) Section of skin of the Gymnophionan, Epicrium. 



