HABITS AND FACULTIES. ^95 



the lAmacidce, whose means of protection, and whose 

 chances of preservation are much less than those of the 

 ffelicidce, the number is much greater than in the latter. 

 The number of eggs produced by two individuals of 

 Limax agrestis kept in confinement by Dr. Leach was, 

 in the course of rather more than a year, seven hundred 

 and eighty-six. It usually amounts to at least three 

 hundred per annum. The other species, though not 

 equally prolific, multiply greatly ; and each pair of the 

 various species of Helicidce produces, annually, from 

 thirty to one hundred eggs, aud perhaps more. The 

 young of the Limacidce complete their growth and re- 

 produce their kind sometimes within the year of their 

 birth, and always as soon as the second year ; and the 

 species of the other families are believed not to require a 

 much longer time to attain maturity. This rapid 

 increase replaces the numbers annually destroyed, and 

 maintains the species in their relative importance. 



Their extreme tenacity of life is manifested in every 

 stage of growth, from the egg to the mature animal. The 

 eggs of Limax have been so entirely desiccated that their 

 form has disappeared, and there remained only a thin 

 skin, friable between the fingers. In this condition they 

 have been kept for years ; and yet a smgle hour's expos- 

 ure to humidity was suflScient to restore their form and 

 elasticity.! They have been dried in a furnace eight 

 successive times, until they were reduced to an almost 

 invisible minuteness, yet in every interval have regained 



' Bouchard-Chantereaux, Ipc. cit. p. 15. 



