INNERVATION OF INTEGUMENT OF CHIROPTERA 303 



Ringer's solution, and small pieces of tissue fixed in a cold 8 per 

 cent solution of ammonium molybdate in distilled water. The 

 tissues were then dehydrated, cleared in xylol, and imbedded in 

 paraffine. Sections of 20^ were thick enough to enable one to 

 follow the nerve fibers some distance, and sufficiently thin to 

 admit ample light. For checking results other methods of pre- 

 paring material were employed. The killing and fixing fluids 

 used for this pvu'pose were corrosive sublimate and acetic acid, 

 Zenker's fluid, ammoniacal alcohol, and 10 per cent formol. 

 The stains used included silver nitrate (Cajal method for nerve 

 fibrils), carmalum as a counter stain for methylene blue, Mallory's 

 connective tissue stain, Heidenhain's iron hematoxylin, Hanson's 

 hematoxylin and orange G, and Delafield's hematoxylin and 

 eosin, the last of which proved the most satisfactory for general 

 use. 



OBSERVATIONS AND DISCUSSION 

 GENERAL STRUCTURE OF THE INTEGUMENT 



1. Integument of the body 



The skin of the body of bats is covered with hair which, as 

 Allen ('93) has found, varies in different regions in texture and 

 amount. In general, the crown of the head, the neck, the sides 

 of the under surface of the body, the rump and the pubis have a 

 thick pelage, while the distal portions of the ears, the soles of the 

 feet, the mammae and the external genitalia are almost naked. 

 The snout is scantily clothed, but shows a limited number of 

 vibrissae which arise from wart-like structures. 



In different regions of the body the skin varies greatly in thick- 

 ness. The integument of the face is the deepest ; that of other 

 parts of the body diminishes in depth gradually in the following 

 order: palmar region, plantar region, rump, ventral thoracic 

 region, crown, and dorsal thoracic region. 



As a rule, some difficulty is experienced in distinguishing all 

 the layers commonly found in the human integument. In the 

 epidermis the Malpighian or deeper stratum can be readily 

 made out. Its deepest layer is made up of subcolumnar cells. 



