36 STANDEN : OBSERVATIONS ON REPRODUCTION OF DART. 



have shown great excitement, constantly crawling over 

 each Other and repeatedly using darts. 



April 2. — Both show signs of exhaustion. 



April 4. — Snails feeding quietly, mostly eating chalk. 



April ^.—Ymd them again actively attempting to pair; sinistral 

 one especially eager, but dextral snail obstinately ap- 

 proaches head to bead all the time I watch. 



April 7. — This morning find pair of darts lying free on a leaf 

 Both are perfect and unbroken. Snails quiet and not 

 feeding. 



April 14. — Snails quite recovered from last attempt to pair, but 

 do" not notice each other. Take out the Meols snail 

 and again put in the former one, which the other 

 appears to recognise. 



April ly. — This morning find snails pairing. In the evening 

 notice that a dart has pierced quite through the fleshy 

 part of the sinistral one's foot, and is evidently causing 

 the animal much uneasiness. Another dart — presum- 

 ably that from the sinistral one — was sticking to side of 

 glass. Examined this carefully, but could see no differ- 

 ence to others. 



April 18. — The dart still troubling the sinistral snail, so with- 

 draw it with forceps, unbroken. It was embedded quite 

 half its length in the foot, about mid-way between the 

 head and tail of the animal, and had gone completely 

 through, the point being about \ inch out, projecting 

 upwards towards the shell and slanting in the direction 

 of the animal's head, which would seem to indicate its 

 having been thrust into the position it occupied by the 

 other snail, and not picked up by accident during the 

 act of crawling. This time I have noticed more hopeful 

 signs of actual coition than hitherto; the genital organs 

 pressed closely together and merged in each other, re- 

 maining thus for from ten to fifteen minutes at a time. 



J.C., vii., April, 1892. 



