192 MORRILL. 



EXPLANATION OF PLATE XIL 



Fig. I. Anterior surface of free ray oi P. palmipcs Storer, when in the resting 

 position, showing ridges r and r' covered with papillae and terminal knob k. 

 Drawn by R. Takano. X 6. 



Fig. 2. Posterior surface of same showing reentrant angle a, marginal papillae 

 /, and terminal knob k. X 6. Drawn by R. Takano. 



Fig. 3. Maceration showing dorsal view of anterior portion of central nervous 

 system of P. palmipes Storer, with the branches of the three first spinal nerves, \, 

 II, and III ; Ol.Ji. and Ol.h. nerve and bulb ; Op.it. and Op.l. optic nerve and lobe ; 

 Cb. cerebrum ; chl. cerebellum ; ac.l. six pairs of accessory lobes on .spinal cord ; 

 I, 2, 3, main branches of third spinal nerve (III) : A and B, divisions oi 2 ; a and 

 d, principal secondary divisions of i ; c and </, divisions of A ; e, anterior branch of 

 3; /a. continuation oi B ; k, I, and m, portions of dermal covering at tips of rays 

 to show distribution of the nerves distally ; n.f.r. nerve fibres of rays, one branch 

 being distributed to each half of the ray; g, h, i, and/, branches of 3; <:, a nerve 

 of the branchial plexus connecting second, II, and third, III, spinal nerves; g"\ 

 ganglionic enlargement of the third, III, spinal nerve. X 2. 



Fig. 4. Ventral surface of same preparation ; 771. r. motor root ; s.r. extremely 

 large sensory root ; In. infundibulum ; l.i. lobes inferiores ; IV and V, fourth and 

 fifth spinal nerves. X 2. 



Fig. 5. Cross section of free ray of P. pal77tipes Storer, made ^ inch from 

 distal end ; a, p, 0, and /, anterior, posterior, outer, and inner surfaces ; c, thickened 

 cuticle shown on surfaces forming reentrant angle r ; i and 2, bones of ray; d, 

 blood vessels ; «, nerves. X 30. 



Fig. 6. Cross section of free ray of P. evolans Gill, ^ inch from distal end. 

 The letters are the same as in Fig. 5. X 30. 



Fig. 7. Vertical section of a papilla of free ray of P. Pal77iipes Storer ; c, 

 cuticle ; b, proximal layer of epidermal cells ; /, peripheral layer ; sp, subepidermal 

 plexus ; 7tf, nerve fibers. Obj. 6 Verick ; cam. luc. Abbe. Gold chloride prepara- 

 tion. 



Fig. 8. Cross section of epidermis of P. evolans Gill. The parts are indi- 

 cated as in Fig. 7, b.vi. basement membrane ; s.c. sensory cell. Obj. 6 Verick ; 

 cam. luc. Abbe ; gold preparation. 



P'lGS. 9 and 10. Similar to Fig. 8. 

 Figs. ii. Sensory cells from P. evolans Gill, showing nerve fibers, 7if, cuticle, c ; 

 nucleus of cell c and terminal enlargement of cell i.e. Gold chloride preparation. 

 Zeiss, oc. 4, y'j oil im.; cam. luc. Abbe. 



Fig. 12. Golgi preparation of epidermis of P. palmipes Storer, showing distri- 

 bution of nerve fibers. Zeiss, oc. 4, obj. D. 



Fig. 13. Similar to Fig. 12, showing portion of subepidermal and epidermal 

 plexii with sensory cell. Zeiss, oc. 4, -^^ oil im., cam. luc. Abbe. 



Fig. 14. Similar to Figs. 12 and 13. Oc. 4, obj. D.; cam. luc. Abbe. 



Fig. 15. Golgi preparation similar to 12, 13, and 14. sp, nerve fibers as they 

 leave the subepidermal plexus. Zeiss, oc. 4, y^^ oil im.; cam. luc. Abbe. 



Fig. 16. Similar to preceding. Zeiss, oc. 4, obj. D.; cam. luc. Abbe. 



Fig. 17. An isolated sensory-cell and nerve fiber from methylen blue prep- 

 aration. 



