318 



EDWARD C. DAY 



the end, weighted with a bit of tinfoil and soaked in a chemical 

 solution of NaCl 2n, NaOH n/10, or quinine 10 per cent, and 

 lowered on to the tentacles likewise evoked an ejection reaction. 

 I operated on six Ascidiae mentulae as follows : three incurrent 

 siphons were severed proximal to the oral tentacles (fig. 2) and 

 three distal to them (fig. 1); the excurrent siphons of the latter 



.,,.y, .., 



Figs, land 2 Two Ascidiae mentulae operated on as shown by dotted lines: 

 in Fig. 1 the incurrent siphon (A) was amputated distal to the circlet of oral 

 tentacles, in Fig. 2 proximal to the tentacles; excurrent siphon (6) also cut off 

 of the first animal. Nerve ganglion is shown as a black spot near the crotch 

 of the siphons. 



Fig. 3 A regenerated Ascidia mentula. Twenty-four days after the incurrent 

 siphon had been cut off carrying the nerve ganglion (gn) with it, a new siphon 

 and ganglion had been regenerated and a coordinate response of both siphons 

 was obtained upon stimulating either siphon independently. 



three were also amputated a half inch from the tip. The am- 

 putated pieces opened immediately after the operation, but 

 were unresponsive to chemical stimulation. 



The following day when crystals of quinine were dropped on 

 to the tentacles of the amputated siphons, it caused them to 

 rise up. Crystals dropped on the lip-lobes of both incurrent and 

 excurrent amputated siphons caused local contractions of the 



