TERMINATIONS OP NERVES IN TORTOISE-SHELL. 569 



DESCRIPTION OF PLATE XLIII, 



Illustrating Dr. John Berry Haycraft^s paper on " Termina- 

 tions of Nerves in the Nuclei of the Epithelial Cells of 

 Tortoise-shell." 



Fig. 1.— Section through the lower part of the tortoise-shell, the sub- 

 jacent connective tissue, and part of the bone of a costal plate. A. Lower 

 laminae of horny layer of tortoise-shell. B. Cells of rate, with big nuclei 

 and deep ridges passing into subjacent connective tissue, (e) Process — 

 profile view of a ridge — of connective tissue running into epithelial cell. 

 D. Pigment-cell in tissue around nerve-fibres. H. Sheath common to two 

 nerve-fibres, m. Outer covering of granular modified connective tissue. 

 K. Inner part of nerve-sheath, consisting of granular non-nucleated connec- 

 tive tissue. 0. Spot in centre, probably an axis-cylinder. E. Bone. 



EiG. 2. — Longitudinal view of a nerve considerably smaller than the one 

 represented in transverse section (Fig. 1). 



Fig. 3.— Part of a sensitive spot; the tortoise-shell is viewed from below. 

 X 250. A. Centre of spot. Branching nerve-fibres seen ending in nuclei of 

 epithelium. Border of cells not seen because of low power used. B. At 

 periphery of spot, where most of the epithelial cells are unconnected with 

 nerve-fibres. 



Fig. 4. — Part of the same highly magnified, x 800, A. Nucleus outside 

 sensory spot. It contains chromatin filaments. B. Nucleus that has shrunk 

 within nuclear cavity. c c. Nerve- fibre passes into nuclear cavity, and 

 apparently ending in the chromatin of the cell, the rest of the nuclear cavity 

 being filled with clear, almost colourless material, e e e. Nothing is to be 

 seen inside the nuclear cavity except the knobs terminating the nerves. The 

 rest of the nucleus has probably shrunk around this. E. Towards centre of 

 spot the outlines of the epithelial cells are very indistinct. 



