348 



MOLLUSCS. 



itself. About a thousand species have been described. They are most numerous 

 in Europe and Eastern Asia, only a very few species being known from South 

 America. Achat ina is one of those genera the scope of which has been greatly 

 altered since it was first founded by Lamarck. In those days any land-shell with 

 a notch or truncation in the pillar-lip of the aperture was considered an Achatina. 

 It is, however, now reserved for a group of large snails which are only met with 

 in Africa, Madagascar, and a few other adjacent islands. They have fine handsome 

 shells, vividly painted with more or less wavy stripes, and covered with a thin 

 periostracum. A. variegata, in the tropical forests of West Africa, is sometimes 

 7h inches in length, and the largest of all the living land-shells. 



The members of the extensive family Achatinellidcv are inhabitants of the 

 Sandwich Islands, and occur in no other part of the globe ; the species being all 

 small, and many of them both dextral and sinistral. Some are found on trees 



I ■ v ^v 





agate-s> t ail (A chatina fulica). 



and shrubs, whilst others are always met with on the ground. Mr. Barnacle has 

 given an interesting account of the production of musical sounds by these little 

 land-snails. He described the sound as resembling that of hundreds of iEolian 

 harps, and believed it was produced by the friction of the shells against the bark 

 of the trees upon which the snails were crawling. 



The amber - snails (Succineidce) bear a strong family likeness to one 

 another. The shells are all very fragile, oblong, yellowish, or reddish, with a more 

 or less exserted spire and a very large body- whorl. They are found in damp 

 situations, and have even been observed crawling beneath the water, upon which 

 they can float in a reversed position. They are vegetarian in their diet, and 

 deposit their eggs on the stems and leaves of aquatic plants, and also upon stones 

 or other substances near the water's edge. Species of Succinea occur in most 

 parts of the world, being met with in such remote localities as Greenland, 

 Patagonia, India, Japan, Australia, and the South Sea Islands. The species 



