APPENDIX. 307 



Many of the species of Helices begin to reproduce be- 

 fore they reach their full growth. 



The eggs of most of the Helices, of JBulimus obscurus, 

 Clausilia nigricans, and Balea, are opake or opaline and 

 isolated ; those of H. virgata are transparent. The eggs 

 of H. pulchella are united together into the form of a cup, 

 often three or four times as large as the animal and its 

 shell. Vitrina pellucida, and Succinea also, unite the 

 eggs into a mass with a gelatinous matter : they are 

 quite hyaline. The eggs of Bidimus obscarns are large, 

 roundish oval : those of Clausilia nigricans are ovoid, 

 and very large for the size of the animal, being nearly 

 as large as the mouth of the shells : those of Balea are 

 large and globular. He observes that H. virgata is very 

 insensible to cold, for they do not hybernate even when 

 the ground is covered with snow ; and H. revelata lives in 

 woods, on the young alders of two or three years' growth, 

 eating the leaves, and resting on the under side of them 

 during the heat of the day. 



Deshayes {Lam. Moll. viii. 178.) refers the Turbo 

 juniperi of Montagu to Pupa avena of Draparnaud, in- 

 stead of Pupa secale, though he properly refers Vertigo 

 secale of Dr. Turton's Manual to that species. He also, 

 probably by a mere slip of the pen, has given England, 

 among others, as the habitat for Pupa doliolum Drap. 

 (Hist. viii. 183.) 



The Conovulus denticulatus feeds on the detritus of 

 marine plants and rotten wood ; they lay 12 or 13 eggs 

 in the month of June and September, united by a viscid 

 matter into a small mass, which is fixed under the more 

 humid stones. The eggs are globular, yellowish, and 

 quite diaphanous: they are hatched about the 15th day, 

 and the animals reach their full size about the end of the 

 second year. They do not hybernate. 



The following table respecting the eggs of LymneadcB 

 is drawn up from M. Bouchard's observations ; the first 

 column giving the form of the masses of eggs ; the second, 



