8 C. M. CHILD. 



they can readily be counted. A considerable amount of material 

 fixed for this purpose was lost by accident when too late to re- 

 place it, so that exact data cannot be given at present. The 

 decrease in the number of tentacles with increasing distance from 

 the oral end is, however, always noticeable even on cursory ex- 

 amination of the pieces. 



Another spieces was also employed for this purpose, viz : the 

 small, whitish, undetermined species mentioned in the preceding 

 paper. In this form the tentacles are much less numerous than 

 in C. solitarius, and can usually be counted without difficulty in 

 the living specimen. This species differs somewhat from C. soli- 

 tarins in the extent of regenerative capacity, but the course of 

 regeneration is the same, and since the structure is in general 

 similar. to that of the other members of the family, the results 

 obtained from this species may be accepted as typical. In all 

 cases the regenerated tentacles were counted only after they had 

 attained a length of several millimeters ; time being thus afforded 

 for the establishment of the small tentacles in the growing region, 

 which sometimes regenerate somewhat later than the others. 

 Only marginal tentacles were counted since the labial tentacles 

 are fewer in number than the intermesenterial chambers and re- 

 generate less regularly than the marginal tentacles. The follow- 

 ing series are given as examples : 



Series 2, October 7. Original number of marginal tentacles 

 2 1 . After removal of disc and tentacles the 



D 





B 



E 



body was cut into five pieces, A, B, C, D, E 

 (Fig. 8). Number of marginal tentacles re- 

 generated A, O, died ; B, 15 ; C, 14 ; D, 13 ; 

 E, o, did not regenerate. 



Scries 5, October ig. Original number of 

 marginal tentacles 19. After removal of disc 



and tentacles body cut into five pieces, A. B. 



FIG. 9. 

 C, D, E (Fig. 9). Number of marginal ten- 



FIG. 8. tacles regenerated : A, o, died ; B, 17 ; C, I 5 ; D, 



13 ; E, o, did not regenerate. 



These two series are sufficient to show that the number of ten- 

 tacles regenerated depends on position and has no relation to size 

 of the piece. In both series the piece B is only half the size of 

 C, yet it regenerates a larger number of tentacles. 



