344 JOURNAL OF CONCHOLOGY, VOL. II, NO. II, JULY, I906. 



two rough drawings of the snails in the position of foot-sole to foot- 

 sole and organs extended. These drawings I have given to Mr. J. W. 

 Taylor, as he thinks they may be of use to him in his Monograph. 



Although the attempt to effect a union between a sinistral and 

 dextral Helix pomaiia was not successful, the observations I made 

 are not uninteresting as shewing the method adopted by this species 

 in pairing, and also how soon a new dart may be formed when one 

 is lost. The nearest approach to actual coition occurred when 6". 

 exserted G.o. and d.s. and thrust dart into G.o. of D. The genital 

 organs on this occasion were close together and almost merging into 

 each other. 



The use of the Helicine dart was fully demonstrated on each of 

 these occasions and confirmed the opinion held by most naturalists 

 nowadays that its function is to induce excitement prior to sexual 

 union. In all I obtained five darts, only three, however, being per- 

 fect; the time occupied in their renewal being from twelve to fourteen 

 days. This time, however, is the time which elapsed between each 

 of their attempts at pairing, and the formation of the dart may, of 

 course, have been completed in less than twelve days. 



Both snails were infested with mites which ran all over the body 

 and in and out of the branchial orifice without the slightest heed being 

 paid by the snails. The only time that they appeared to notice them 

 was when a mite ran along the tentacle and over the eye, when the 

 snail would give a slight twinge and withdraw its tentacle. This I 

 observed more than once. 



Having in mind Dr. Scharff's query in \h\s Joi(r?ial (vol. 4, p. 310) 

 as to whether molluscs are able to distinguish sounds, or merely con- 

 cussions, in order to be aware of danger, on several occasions I gave 

 the glass tank a sharp knock when the snails were going through their 

 curious actions, and on each occasion they instantly withdrew their 

 heads and tentacles and remained quiescent for a short time, still 

 retaining the position of foot to foot. I am inclined to think that it 

 was more the concussion than the sound which affected them, as the 

 snails were subjected to plenty of sounds and noises of one kind or 

 another, which they did not appear to notice. No doubt the high 

 pitch of excitement to which the snails had worked themselves would 

 materially affect them on these occasions and tend to make them 

 more sensitive than usual. 



Regarding the sense of smell in these creatures I noticed that the 

 snails in many instances lowered their tentacles when eating, but 

 whether for purposes of sight or smell I cannot say (see \\i\% Journal, 

 vol. 4, p. 312). 



