Fig. 2. Odor-aversion learning was not affected by the control treatment, but was completely abolished by amputation of both stets of tentacles, the STs and ITs. (Ai) Experimental schedule of the pre-conditioning control treatment. (Aii) The avoidance rate (%) of the slugs with the pre-conditioning control treatment. (Bi) Experimental schedule of the post-conditioning control treatment. (Bii) The avoidance rate (%) of the slugs with the post-conditioning control treatment. (Ci,Cii) Odor-aversion learning was affected by the amputation of both STs and ITs. (Ci) Experimental schedule of the post-conditioning ST+IT amputation. (Cii) The avoidance rate (%) of the slugs with the post-conditioning ST+IT amputation. The conditioning, the control treatment (or ST+IT amputation), and the retention test are indicated by •, and , respectively. The numbers above the columns indicate the number of slugs used for the retention tests. ^*P<0.05 and ^**P<0.01 by ² test. n.s., not significantly different.