TERMINATIONS OF NERVES IN TORTOISE-SHELL. 563 



Terminations of Nerves in the Nuclei of the 

 Epithelial Cells of Tortoise-shell, 



By 



John Berry Haycraft, ]II.I>., I>.Sc., 



From the Physiological Laboratory of the University of Edinburgh. 



With Plate XLIII. 



The land tortoise (Testudo greeca), so commonly imported 

 into England from the south of Europe, appears to be a very 

 sluggish animal. This is not really the case, and its move- 

 ments on a hot summer day are the reverse of phlegmatic. 

 In this condition its carapace is sensitive to the slightest 

 impact. If the carapace or plastron be very gently tapped, 

 the nearest leg is alone withdrawn, a heavier tap causing a 

 withdrawal of its whole body. We have here, therefore, a 

 structure which is a true sensitive surface, and like the soft 

 skin of a frog or of a man, it is brought into relation- 

 ship with the central nervous system = Like the soft skin of 

 other animals it may be mapped out into areas, from which 

 the nerve-fibres passing to the spinal cord are all especially 

 connected with outgoing motor nerves, so that the definite 

 reflex movements of limbs as already described may come 

 about. 



The above experiment naturally suggested that the sensory 

 nerves passed right through the thick bone of the carapace and 

 plastron, and ended near the outer surface, either in the 

 epithelial tissue of the tortoise-shell itself or in the layer of 

 connective tissue which unites it to the subjacent bone. 



After removal of a scute of tortoise-shell the connective 



VOL. XXXI, PART IV. — NEW SER. P P 



