INNERVATION OF INTEGUMENT OF CHIROPTERA 315 



number of the structures in question are situated on the surfaces 

 of the cells (fig. 7, es) . Others appear to be within the cytoplasm. 

 However, it is frequently possible by focusing to see that these 

 end-knobs are after all on the borders of the cells. If all were 

 completely stained, it is not improbable that the remaining end- 

 knobs could be shown to be intercellular. 



So far as the writer has been able to ascertain the only refe*'- 

 ence to free nerve terminations in the epidermis of bats is that 

 of Botezat ('08). The study of this investigator was made 

 principally on the nerves in the epidermis of the dog's nose, but 

 he mentioned the finding of intracellular end-knobs ('Endknopf- 

 en') in the skin of the nose of the bat. He held that the free 

 nerve terminations in the epidermis, not only of bats, but of all 

 classes of vertebrates, are intracellular, though none of his figures 

 indicates it. Retzius ('92) showed free nerve terminations (in- 

 tercellular) in the epidermis of the lip of the human foetus. Of 

 free nerve endings in the epidermis of the mouse and of the rabbit 

 he made the following statement: "Die feinen, varicosen Nerven- 

 fasern verzweigen sich und endigen im Rete Malpighii inter- 

 zellular ohne jeden directen Zusammenhang mit Zellen." Van 

 Gehuchten, in 1893, described free nerve terminations in the 

 epidermis of the face, lip, ear, paw and tail of the white mouse and 

 white rat. He likewise found the free nerve endings to be inter- 

 cellular. He stated, "Partout nous avons trouve I'existence de 

 fibres nerveuses intra-epidermiques se ramifiant et se terminant 

 librement entre les cellules epitheliales." While Dogiel ('03) did 

 not hold intracellular endings as out of the question, yet he was 

 strongly of the opinion that the free nerve terminations are 

 intercellular. 



2. Nerve endings on hairs 



While the innervation of hairs has for some time been a field 

 of fruitful investigation, there still remain some unsolved prob- 

 lems in connection with the hair of Chiroptera. In recent years 

 especially, more attention has been directed toward the inner- 

 vation of tactile or sinus hairs than toward that of the hairs of 

 the pelage. The writer's descriptions will be confined wholly 

 to the latter. 



