APPENDIX. 



SINCE the greater part of this work has been printed, M. 

 Bouchard Chantreux has sent me his " Catalogue des 

 Mollusques Terrestres et Fluviatiles du Pas de Calais," 

 which contains some interesting details on the habits and 

 manners, and especially on the reproduction of these 

 animals. Many of the facts recorded in this work must 

 have been observed by most collectors of European shells ; 

 but they have been left for M. Bouchard to publish. 

 From this work I shall make the following abstract : 



He observes that the Arions and Limaces are semi-noc- 

 turnal animals; the eggs of Arions are separate, and co- 

 vered with a hard calcareous coat, while those of the slugs 

 (Limaces) are covered with a transparent coat, and often 

 united together by a membrane like a string of beads. 



The land soles (Arion) lay about 70 to 100 eggs be- 

 tween May and September. They vary from 26 to 40 days 

 in hatching, and the animals attain their full growth in a 

 year ; but they begin to deposit their eggs a month or 

 two before that period. The young of A. ater is dull 

 brown, with yellowish sides. The eggs of A. hortensis 

 are very phosphorescent for the first 15 days after they are 

 laid. M. Bouchard says that the true A. hortensis has 

 no shell ; he therefore doubts the species described by 

 MM. Brard, Grateloup, Michaud, and Millet, which is 

 said to produce Limacella concava; and I find that, by an 

 oversight, I have referred this Limacella both to Arion 

 hortensis and Limaxflavus. 



The eggs of the slugs (Limaces) are laid between May 

 and September. They are hatched in about 25 or 30 

 days, and the young reach their full size near the end of 

 the year. Limax cinereus lays about 50 or 60, and Zz- 

 max agrestis is much more prolific, as it continues laying 



