STIMULATIONS IN NUDIBRANCHIATE MOLLUSKS 



429 



to fifteen min. ate as follows. Ten niin. treatment, 25 mm.; 

 15 min, treatment: 17, 19, 20 and 25 mm. The other five had 

 their food treated for 1 hr. and 40 min. in the same solution and 

 the amounts these ate, respectively, were: 0, 12, 17, 20 and 50 

 mm. The same ten specimens, on another day, ate as follows, 

 the food being treated for 15 min. in M 0.05 MgSOi: 



It was noted that the response of the organism when stimulated 

 with M magnesium sulphate was 0. That is, it notices the 

 stimulus, but does not attempt to avoid it definitely. One 

 might, therefore, expect a result as noted above w^hich is nearly 

 similar to the results obtained from the control (see the table 

 below). Fed on gonads treated with 0.1 M sodium sahcylate 

 for 10 min. the result was that all moved away from it at first. 

 Three min. later, one ate 30 mm. which had been treated for 

 30 min., one nibbled at it and bit it into parts, but did not eat 

 it. The others moved away from it. The reaction of the organ- 

 ism to M sodium salicylate is from to ; it was, 



therefore, no surprise that the organism did not want to feed on 

 this food even though it was treated in a much more dilute solu- 

 tion as compared with those mentioned above. The Nudibranch 

 ate food treated for 6 hrs. in glycerol: 40, 40, 40, 40, and 50 mm. 

 The reaction to glycerol was 0. The same individuals at the 

 same hour also ate, respectively, 50, 17, 25, 17, and 50 mm., 

 treated in 2 M ethyl alcohol. The average amount of food 

 taken at this time was: 90, 57, 65, 57 and 100 mm. The response 

 to 2 M ethyl was ® or nearly +. The other five would not 

 take food treated in 2 M ethyl, but when it was treated in M 

 ethyl they ate: 50, 50, 50, 50, and 40 mm., respectively. The 

 amount of food taken, which was treated in sat. sol. of quinine 

 sulphate, was as follows: a, bit at it and spat it out; b, do. do.; c, 

 ate 25 mm. ; d, ate 50 mm. at once, and e, avoided it altogether. 



