308 MICROSCOPIC ANATOMY OF THE ORGANS. 



places. These free endings appear in the form of irregularly 

 outlined end plates. 



Other nerve-endings in the connective tissue have the form 

 of corpuscles. The so-called Grandry's corpuscles have a cer- 

 tain similarity to Merkel's tactile bodies (Fig. 233). They are 



FIG. 233. 



Tactile cell , n~ ^m .- -^^^iv; vr ~ e 



'uv if*iv j*j.mw. 



Connective- 

 tissue 

 capsule 



Grandry's tactile corpuscle, composed of two tactile cells and a tactile sheath. From a 

 vertical section through the cere of a duck's bill. X 400. 



about 50 (i in diameter, and are surrounded by a connective- 

 tissue capsule. Inside the capsule there are present one or 

 more tactile cells and a tactile disc representing the final termi- 

 nation of the nerve fibre. The fibre loses its sheaths at the 

 point where it passes through the connective-tissue capsule, 

 and the naked axis cylinder spreads out at the end to form 

 the tactile disc. It may undergo no division, or may give 

 rise to two or more branches, each of which becomes flattened 

 and forms a tactile disc. These axis cylinders are bounded 

 on both sides by tactile cells. In a corpuscle that contains 

 only one disc we find two tactile cells which are somewhat 

 kidney-shaped. When two discs are present, three tactile cells 

 are found ; with three discs, four cells, etc. The largest cor- 

 puscles are found in the duck's bill, and contain four discs 

 and five tactile cells. The tactile discs are thinner at their 

 periphery than in the centre. In these discs primitive fibrils 

 can be made out by special methods. These run into the disc 

 from the place where the axis cylinder enters, like the rays of 

 a fan. The discs and tactile cells lie parallel to the outer sur- 

 face of the skin. The cells show in the central part of their 



