341 



ATi ATTEMPT TO BREED FROM A SINISTRAL 



HELIX POMATIA, 



With Notes on the Reproduction of the Dart. 



By J. WILFRID JACKSON. 



(Read before the Society, December 13th, 1905). 



On May loth, 1904, I received from Mr. F. B. Jennings, of London, 

 a very fine and almost full-grown sinistral specimen of Helix pomatia 

 which a friend of his had had the good fortune to find at Box Hill, 

 Surrey, on the ist of the month. In coming through the post the lip 

 of the shell was unfortunately fractured, but the snail eventually made 

 this good. After exhibiting the specimen at one of the meetings of 

 the Conch ©logical Society I entered into negociations with Mr. 

 Jennings with a view to retaining possession of the snail for breeding 

 experiments, and Mr. Jennings very kindly allowed me to keep it. 

 As he had also sent me a living dextral specimen I decided to make 

 experiments with them after the manner adopted by Mr. R. Standen^ 

 with a sinistral Helix aspersa some years ago. 



The following are the more interesting notes from my diary, and 

 for convenience I have adopted the abbreviations as under:— Z?= 

 dextral snail; D.s.=:dart sac; ^.=sinistral snail; G.o.=generative 

 organ. 



May 14TH, 1904. — Placed both snails in a large glass tank bedded 

 with earth, pieces of chalk, and limestone mortar. Put in a supply of 

 cabbage leaves which the snails commenced to devour at once. 

 Noticed 6". had repaired its shell. 



May 15TH. — Noticed very strong desire to pair on the part of both 

 snails. Animals in peculiar position, foot-sole to foot-sole, and 

 standing erect on tips of tails, and fondling each other with tentacles 

 and palpi; mouths also in close contact. Snails emitting a curious 

 sibulant smacking sound. G.o. of D. protruded forcibly towards base 

 of right tentacle of S., but genital aperture being on left side in S. 

 coition impossible. 



May I 6th. — Snails have evidently been very active during night. 

 Quantity of thick slime about. Found one dart in mass of mucus. 

 Dart perfectly formed with exception of annulus which is missing. In 

 the evening noticed Z>. was partly out of shell and had turned back 

 its head and was gnawing away at the aperture of its own shell, the 

 noise being quite audible. Later — both snails feeding quietly. 



May 23RD. — Snails very active and feeding voraciously on lettuce, 

 S. occasionally eating limestone mortar. 



X /. Conch., vol. 7, p. 33. 



