INTEGUMENT 



21 



and cells with thread-like and vacuolated contents have also been 

 described in Anuran larvse. Later on, immediately before meta- 

 morphosis, numerous muliicdlular glands of alveolar structure 



FIG. 14. SKIN OF LARVA OF SALAMANDER (Salamandra maculosa). 



a, stratum corneum ; It, stratum Malpighii ; Co, derm ; OS, striated border ; 

 Ep, epiderm ; LZ, Leydig's cells (unicellular mucus glands). 



(cf. p. 20) appear in adaptation for terrestrial life. These have 

 nothing to do with the unicellular larval glands : their great 

 abundance is very characteristic of the Amphibian skin (Figs. 15 

 and 16). As regards their distribution, they may be scattered singly 

 throughout the skin, or arranged in groups in Anurans chiefly 



FIG. 15. SEMIDIAGRAMMATIC SECTION THROUGH THE SKIN OF ADULT 

 SALAMANDER (S. mactilom). 



Co, derm, in the connective tissue stroma of which (B) the various sized integii- 

 mentary glands (A, C, D, D) lie embedded ; E, epithelium of glands ; Ep, 

 epiderm ; M l , the muscular, and Pr the connective-tissue layer of the 

 glands ; M, the same, seen from the surface ; Mm, subcutaneous layer of 

 muscles, through which vessels (G) extend into the derm; Pi, Piy, pigment 

 cells in the derm ; S, secretion of glands. 



along the back, in Urodeles (and Toads) at the junction of head and 

 trunk (" parotoids") or laterally along the body and in the caudal 

 region (e.g. Spelerpes, Plethodon). These aggregated glands vary 



