1921.] 



The Grey Field Slug. 



453 



•becoioing milky white on irritation, due to innumerable 

 particles of carbonate of lime." 



Slugs, like snails and allied forms, are hermaphrodite. The 

 sex organs are located on the right side, just behind the head; 

 when mating these are extruded and become swollen, distended 

 and globular, the colour being whitish with a tinge of blue. 

 ]\Iating takes place early in the morning, between 4 a.m. and 

 f) a.m., especially on wet or misty mornings, when the ground is 

 very wet. After mating the slugs retreat and hide in tunnels 

 and crevices in the soil. 



Egg-laying commences a])out a fortnight or three weeks after 

 mating, the adult becomijig quiescent shortly before the ova 



A.— Adult slug extended. b.— Slug contracted. 



C— Cluster of Eggs. D.— Egg enlarged. 



E.— Adult slug extended, with sex organs {a) extruded. 



are deposited. The eggs, which are elliptical and practically 

 transparent, are laid separately, but in clusters of as many as 

 no, under moss, vegetation and decaying roots. Lovett and 

 Black quote an interesting observation in connection with the 

 egg-laying habits of slugs: " Stock turnips, which had become 

 pithy and split open, were found with great mas'.^es of eggs in 

 the fibrous and slightly moist interior." 



On hatching, the young slug is whitish in colour. This 

 gradually gives i)lace to pale-grey, which in turn becomes 

 mottled-grey and bi'ownish as development proceeds. The slug 

 attains maturity in from three to four months and mav live 

 for two years oi- longer. 



