(6) 



EXPLANATION OF THE TLATES. 



Fig. 8. rroiilo \iew of a cell, like. fig. 3. 



Fig. ;i. Tlir lassd iiartially tlirust out, ami the rest of 

 the thread distant li\mi the wall, showing that no cell 

 contraction forees it out, liut that it is jimtrudrd by its 

 own act. Tlio granular coating covers the whole cell. 



Fig. li>. Similar to tig. 5, in profile. 



Fig. 11. I'rofde view; the thread extruded, hut not 

 uncoiled. 



Fig. 1'-'. Showing the same as fig. '\ hut more of the 

 thread is out. 



Fig. i:!. The tip of one of the tentacular fringes, a the 

 lasso-cells; h the same as a, in profile; c outer wall; 

 il inner wall; t transparent axis. 3.')0 diameters. 



Fig. 14. Portidus of the elongate shallow furrows of the 

 circmnscrilied area covered by vibratile cilia; the bulli 

 and cap of the eye-speck, the two Ijulbs of the axial 

 funnel, and the eight epidermic bamls of ciliate bodies 

 prolonged from the rows of natatory flappers. '.'."i 

 diameters. 



Fig. 15. The tentacular apparatus as seen from the peri- 

 phery, to show the mode cif the attachment of the 

 ti'utacle to the disk, and the relation of the latter to 

 the double chymiferous tubes ; taken fivjm a half-grown 

 individual. (SO diameters. The betti'r to understand 

 the relations of these parts, a profile view (Fig. t') 



Fi". C. 



a a'^ ch3'uiiferous tube. 



a' entrance to q. 



t wall of the main liorizontiii 



chymiferous trunk. 

 e' wall of the ojiposite side of e. 

 g The base of the tentacle. 

 j tentacular socket, 

 yi aperture of y. 

 y- apex of j. 

 j3 proximal side of y. 

 K the tentacle. 



q point of junction of e and a', 

 ^jj" outer wall of the disk. 

 IJ'" same as ,3". 

 y the inner layer of the disk. 

 y inner layer of the disk at the 



base of the tentacle. 

 ■\/^ the thin proximal wall of a. 

 Y" the same .as y'' . 

 yfff the thickest part of the 



same layer. 



A full account of the structure 

 of this apparatus may be found 

 on page 235. 



of the same apparatus is here introduced, with the 

 same lettering as fig. 15 of PI. II-'. 



Fig. in. A few lasso-ccUs from fig. 17. 5ot) diameter.s. 



Fig. 1 ">■ < >ne of the tentacular fringes, showing the lasso- 

 cells to be arranged side by side in an uninterrupted 

 layer <i h\ here and there the threads are out. 350 

 diametcr.s. 



Fig. bs. Transversely sectional view of a contracted ten- 

 tacular fringe. h the layer of lasso-cells; c & the 

 outer wall ; </ '/' the inner wall ; e the transparent 

 axis. oJO diam. 



Fig. 19. The eye and its cap; the bulb underlying the 

 eye ; the eiiht rows of immovable cilia ; and the 

 oblong shallow furrow, more highly magnified than in 

 fig. 14. 5(1 diameters. 



Figs. -JO, ■_>!. 2'>, and 23 represent the same animal in 

 fiiur dilVcrent views, so that, after a careful study, its 

 firm might be carved from them. 



Fig. "JO. A full-grown individual, seen from the abac- 

 tinal end, to show the organs in their relative position ; 

 the e)e and the shallow olilong fiiiTow of the circum- 

 scril.ied area are nearest the observer; the tentacular 

 apparatus comes next, and the two great main chymife- 

 rous trunks are about the middle of the body. 4 

 diameters. 



Fig. I'l. Same as fig. 20; seen from the actinal end, 

 to show princi]ially the relation of the cellulo-motor 

 systems to the organs ; the mouth is nearest the eye, 

 then come the tentacular sockets, and lastly the two 

 great chymiferous trunks. 



Fi^. "J2. Profile view, in which one of the tentacles is 

 next the observer, the digestive cavity (7/) presents 

 its broad side t<i the eye, and tlie bulljs (/',/■-) of 

 the axial funnel stand right and left. 



Fig. 23. 'N'iew at right angles to fig. 22. The tentacles 

 stand right ami left, as do also the two chymiferous 

 tubes (r /■') which embirace the digestive cavity; the 

 latter (h) presenting its edge to the eye. 



Fig. 24. The enormous cells of the cellulo-motor sys- 

 tems. These are from the radial .system, a the wall ; 

 }i same as a, but contracted anil wrinkled ; c the wa\-y 

 face of \i ; (/ transparent cavity of the cell ; c the 

 sleniler jioints of the cells. 500 diameters. 



Fig. 25. An individual, natural size, swimming with its 

 tentacles trailing behind, and the fringes curved, waved, 

 bent at various sharp angles, anil stretched to the 

 utmost or closely retracted. For other views, see my 

 jiaper in Mem. Amer. Acad. A'ol. IV. PI. I. 



Fig. 2t!. One of the natatory paddles and the subjacent 

 cells of the cellulo-motor systems, to show the relation 

 of the cells of the paddles to those of the motor sys- 

 tem. 50 diameters. 



