1 86 MORRILL. [Vol. XI. 



There are no papillae on the surface of the free rays of P. 

 evolans. The epidermis closely resembles that already described 

 for the faces of the reentrant angle in the free rays of P. pal- 

 Diipes, except that the spindle-shaped cells are crowded together 

 at certain points (Figs. 8, g, and lo), and the cuticle is thinner 

 and does not show perpendicular striae. 



Nerve Termmations . 



The nerves in the free rays form a plexus just beneath the 

 surface of the epidermis (Figs. 7, 9, 10, 13, and 16, sp). The 

 fibers in this plexus are very closely crowded under the papillae 

 in P. palmipcs, and less so beneath the longitudinal ridges in 

 P. evolans. Nerve fibers (Figs. 7, 8, 9, and 10, iif) from the 

 plexus, in both species of Priojiotus, penetrate the basement 

 membrane and pass out between the cells of the inner layer of 

 the epidermal cells, where they divide, sending numerous 

 branches in all directions along the distal ends of the inner 

 layer of epidermal cells. These fibers soon curve outward, a 

 large proportion of them ending free just below the cuticle, 

 while a smaller number are directly connected with spindle- 

 shaped cells (Figs. 10, II, 13, 15, 16, and 17) the outer ends 

 of which extend to the cuticle. A single detached cell and 

 nerve fiber is seen in Fig. 17 from a methylen blue prep- 

 aration. 



The gold chloride preparations agreed very closely with those 

 obtained by Golgi's rapid method. The latter (Figs. 12-16), 

 however, showed much greater detail, and brought out the epi- 

 dermal plexus with great distinctness, a point very imperfectly 

 shown by the use of gold chloride. 



The manner of the nerve ending in the epidermis, between 

 the papillae (Fig. 12) in P. palmipes, was similar to that over 

 the papillae, except that the nerve fibers were widely scattered 

 and nerve cells rarely found. The peripheral nerve fibers in 

 P. evolans were similar to those in the general epidermis of 

 P. palmipcs, but are fewer in number and more easily studied 

 by the gold chloride method. 



