134 C. M. CHILD. 



but still shorter and more sac-like than normal ; marginal ten- 

 tacles 1 2^-15 mm.; labial tentacles 4-5 mm. 



() Distended, form like that of a; marginal tentacles 10-12 

 mm.; labial tentacles about 3 mm. 



(r) Distended, similar to a and b in form ; marginal tentacles 

 78 mm.; labial tentacles 1-2 mm. 



(W) Now completely closed and distended, similar to others in 

 form: marginal tentacles 6 7 mm.; labial tentacles 1 1.5 rnm. 



(i) Has never closed aborally ; oral end not expanded ; minute 

 marginal tentacle-buds visible ; no labial tentacles. 



Series 12. 



September 12, 1902. Six specimens were cut transversely 

 just below the cesophageal region (Fig. 7). Three to be used as 

 controls and three as experimental pieces. 



September 15. - - 3 days after section : In all six pieces the oral 

 end was closed with delicate new tissue and all were partly filled 

 with water. Three of the pieces were now split longitudinally 

 from the aboral end for half their length (experimental pieces), 

 the other three remaining undisturbed (controls). The experi- 

 mental pieces contracted so strongly during this operation that 

 the new tissue closing the oral end was ruptured, but the ten- 

 tacle-forming region was not injured. The cut aboral ends of 

 the experimental pieces are to be opened morning and evening 

 of each day to prevent distension as far as possible. 



September rq. - - 7 days after first operation. Experimental 

 pieces. Have not been distended at any time, although some 

 accumulation of water has occurred in the intervals between the 

 operations ; the oral end of one not expanded and the new tissue 

 merely fills crevices ; two pieces with minute marginal tentacle- 

 buds visible ; in the third formation of tentacle-buds beginning 

 at a few points on the tentacular ridge. 



Controls : All well-filled with water and disc expanded ; the 

 new tissue at oral end forms a distinct central area in consequence 

 of distension ; one piece with marginal tentacles 2 mm.; two 

 pieces with tentacles i mm. 



September 22.- - 10 days after first operation. Experimental 

 pieces. Form of disc in all cases as before ; two pieces with 



