Mammalia: Skin, Muscles, Skeleton 

 Sch 



575 



Fig. 443. Section of hair. (Ap) Erector 

 muscle; (Co) dermis; (F, F l ) layers of 

 longitudinal (outer) and circular (inner) 

 connective-tissue fibers; (Ft) fat; (GH) 

 hyaline layer; (HBD) sebaceous gland; 

 (HP) dermal papilla containing blood- 

 vessels; (M) medulla; (0) cuticle of shaft; 

 (R) cortex; (Sc) stratum corneum; (Sch) 

 shaft; (SM) germinative layer of epi- 

 dermis; (WS, WS l ) outer and inner 

 layers of epidermal sheath of follicle. 

 (Courtesy, Wiedersheim : " Grundriss der 

 vergleichenden Anatomie der Wirbel- 

 tiere," Jena, Gustav Fischer.) 



mammals in which perspiration is produced in sufficient quantity and 

 whose fur is not so thick as to interfere with ready evaporation at the 

 surface of the body (e.g., horse and man), the sweat-glands play an 

 important part in the regulation of the temperature of the body. The 

 oily secretions check absorption of external water by the skin and fur. 



