KUTCHIN. — PERIPHERAL NERVOUS SYSTEM OF AMPHIOXUS. Glo 



distal than at its proximal end, and often bears a knob-like termination. 

 Two apparent points of attachment to the cell are frequently visible; 

 one of these occurs at almost any point on the outer surface of the cell, 

 while the other is at one side of the cell, or perhaps between two cells. 

 While these special cells may possibly correspond to the "thorn" cells 

 (Stachelzellen) noted by Reichert ('70, p. 756), this stiff hair is much 

 too long for such a comparison, nor does it resemble a spine, because 

 of its thickened distal end; neither does it resemble any terminal 

 nervous structure. One interesting feature is the varying length of 

 such "hairs," and their absence from many of the special cells. The 

 "hairs" were nearly always comparatively short in methylene-blue 

 preparations. I suggest that these special cells may be gland cells, 

 and that the "hairs" are hardened exudations adhering to the outer 

 surface. Glands certainly exist in the skin of Amphioxus, and probably 

 receive a nerve supply from the cutaneous plexuses. Attempts were 

 made on hardened material to color the "hairs" with special stains 

 for glands, but none of the material was properly fixed to make such 

 tests of value. If these peculiar cells are gland cells, it is still uncer- 

 tain whether sensory cells are present in the epithelium of all parts of 

 the body. 



Sensory cells are clearly present in the tentacles, and on the mouth 

 border, as described by Dogiel (:02, p. 192-195; Fig. 10, 31, 32). 

 These cells impregnated successfully in certain of my methylene-blue 

 preparations, and nerve fibers could be traced in the tentacles to the 

 region of these cells. I was unable, however, to determine absolutely 

 the connection between the two which in all probability exists in the 

 form already shown by Dogiel. The long distal process of the end- 

 cells in the papillae of the tentacles, figured by Dogiel was clearly 

 evident in my preparations. 



Ventral Nerves. 



Owsjannikow (*68) describes nerve roots arising from the spinal 

 cord at different levels. Although Stieda ('73) thought it probable 

 that this author saw ventral nerve roots, he himself was the first to 

 describe the ventral roots clearly; he notes that they do not lie in the 

 cross-section plane of the dorsal roots, and he found no actual imion 

 between them and the dorsal roots. Langerhans ('76) saw only 

 dorsal roots, and regarded them as carrying motor fibers. Schneider 

 ('79) described each ventral nerve root as arising by several processes 



