APPEXDAGES OF THE Sk'/X 1079 



formed below 1)V a layer nf cells which cnoloso and crown the ijajiilla. Downy 

 hairs are devoid of medulla. The cortex consists of a layer of fusiform cells 

 elongated in the direction of the hair, and these, like tlie medullary cells, are 

 nucleated and contain pigmentary granules. The epidermis or cuticle is a layer 

 of scaly epithelial cells, arranged like the tiles of a roof, hut with the overlapping 

 edges directed upwards. Owing to this peculiar imbrication the edges of the cells 

 of the buried part of the shaft may become reversed when the hair is pulled out of 

 its follicle, and may then present a deceptive appearance like that of fusiform fibres 

 rolled spirally around a stem. 



As the shaft structures approach the papilla they gradually change their char- 

 acter. The l)ulb itself consists of an inner layer of prismatic cells lying directly 

 in contact with the dermic ])apilla, an<l rei»reseiiting the stratum basilaii- of the 

 epidermis; a middle layer of pf)lyhedral cells like those of the stratum Malpighii, 

 and an outer layer of keratinising cells corresponding to the stratum granulo.sum, 

 but devoid of eleidin. 



The papilla is a cone of connective tissue into the centre of which is prolonged 

 a vascular looj) from the subcutaneous plexus. Nerves are not seen in the papilla, 

 but fine twigs have l)een traced into the deeper part of the follicular wall, there 

 losing their myelin and forming terminal fibrils, some longitudinally, some circu- 

 larly arranged, outside the hyali!i layer. The special tactile hairs of the lower 

 animals present a more complex nervous and vascular apparatus, but these are not 

 represented in man. 



