TACTILE HAIR OF THE WHITE RAT 5 



upper part of this sinus when filled is practically closed by the 

 ringwulst which separates it from the entirely free space above, 

 the ring sinus. 



Arteries and veins. The fibrous sheath is supplied with the 

 ordinary nutritive blood vessels. These are particularly numer- 

 ous in the middle layer of the sheath. 



The large follicle artery enters with the main nerve at about 

 the lower third of the sheath. It here divides and sends a branch 

 to the lower part of the follicle and several branches upward 

 which in turn divide and encircle the follicle longitudinally as 

 far as the ring sinus into which they empty from below. To do 

 so they run close to the walls of the follicle between them and 

 the ringwulst to which they give many capillary branches. 



Besides this main artery there are other smaller ones which 

 come from the subcutaneous plexus and penetrating the walls of 

 the dermal sheath debouch into the sinus at about the same 

 place as the others. 



More numerous than these vessels from below, however, are 

 those which come down from the upper vascular plexus which 

 lies just below the corium papillae. They accompany the nerves 

 for the nerve ring about the neck of the follicle and open into 

 the roof of the sinus just below the ring. In good preparations 

 there may be seen a series of such perforations encircling the 

 follicle in the constriction of the walls which form this roof. 



I never saw any large veins in the follicle and think the venous 

 outlets are, as Bonnet ('78) and Dietl ('73) describe them, through 

 the outer coats of the bulb emptying into the skin veins. 



Muscles. There is a veritable network of muscles surrounding 

 the follicle. For the most part these are skin muscles and they 

 help to obscure the real muscular attachments of the bulb. 



There are longitudinal muscle fibers running down from the 

 surface of the skin which have a membranous attachment to the 

 walls of the follicle. It is also enclosed by horizontal bands of 

 fibers so that it shares in the general skin musculature. Besides 

 these there are long tendinous cords apparently forming part of 

 the walls of the follicle which run deep down into the subcutaneous 

 tissue and firmly anchor the follicle below. From the upper part 



