HISTOLOGY 



T07 



Maximow and Bloom (73). Dry (30) describes the develoi)ment and suc- 

 cession of the various types of overhairs, underfurs (zigzags), vibrissae, hair- 

 lets, and hairs of the arioles of the mouse. 



Vibrissae, tactile hairs or sinus hairs are long coarse hairs with deeply 

 imbedded hair follicles (22, 23). Between the connective tissue sheath and 



Hair shaft 

 Medulla 

 Cortex 

 Hair cuticle 

 Skin 



Sebaceous gland 

 Ring sinus 

 Hyaline membrane 



Superior swelling of 

 the root sheath 



Pulvinus 



Nerve fibers 



Inferior swelling o 

 the root sheath 



Cavernous sinus 



Connective tissue 

 sheath 



Nerve fibers 



Hair bulb 

 Papilla 



Fig. 46. — Diagram of a vibrissa. (X125.) 



the hyaline membrane of the hair follicle a cavity is present, the lower 

 part of which is divided into reticular spaces by a network of fibers originat- 

 ing from the inner surface of the fibrous sheath, while the upper part con- 

 tains one circular space (Fig. 46). These cavities are filled with blood and 

 form the cavernous and circular (or ring) sinuses respectively. The cells 

 forming the reticular network often contain pigment. Extending into the 

 circular sinus is an oval-shaped projection, the pulvinus. According to 



