300 ]Vr\NUAL OF THE MOLLUSCA. 



beneath the mantle ; foot oval, much smaller than the mantle ; 

 length 3|- inches. Coast of Chili. (Eequires confirmation.) 



Vagintjlus, Ferussac. 



Type, Y. Taunaisii, Ferussac. 



Synonym, Yeronicella, Bl. 



Animal elongated, slug-like, entirely covered by a thick 

 coriaceous mantle, smooth or granulated ; head retractile under 

 mantle ; tentacles 4, upper pair slender, cylindrical, inflated at 

 the tips and bearing eyes, lower pair short, bifid ; foot linear, 

 pointed behind ; sexes united ; $ orifice behind the right ten- 

 tacle, 5 midway on the right side, beneath the mantle ; 

 respiratory and excretory orifices at posterior extremity between 

 mantle and foot. Inhabits forests, in decayed wood and under 

 leaves. 



Distrihution, 20 species. West Indies, South America, India, 

 Philippines. 



Family IV. — Limn^id^. 



Shell thin, horn-coloured; capable of containing the whole 

 animal when retracted ; aperture simple, lip sharp ; apex some- 

 times eroded. 



Animal with a short dilated muzzle ; tentacles 2, eyes sessile 

 at their inner bases ; mouth armed with an upper mandible, 

 tongue with teeth similar to Helix. The Limnseids inhabit 

 fresh waters in all parts of the world ; they feed chiefly on 

 decaying leaves, and deposit their spawn in the form of oblong 

 transparent masses on aquatic plants and stones. They fre- 

 quently glide beneath the surface of the water, shell downwardb. 

 and hybernate or a?stivate in the mud. 



The fresh-water snails (and also Neritina) can lower them- 

 selves from aquatic plants by a mucous thread, and re-ascend 

 hy the same ; a Physa can be lifted out of the water by its thi-ead. 



LiMNJEA,* Lamarck. Pond-snail. 



I Etymology, Limiudos, marshy. 



Type, L. stagnalis, Fig. 128. PI. XII., Fig. 30. 

 Shell spiral, more or less elongated, thin, translucent ; body- 

 whorl large, aperture rounded in front; columella obliquely 

 twisted. 



Animal with a short, broad head ; tentacles triangular, com- 

 pressed; lingual teeth {L. stagnalis) 55.1.55, about 110 rows, 

 central teeth minute, laterals bicuspid, the inner cusp largest. 

 * Adjeolives employed as names for shells should have the feminine termi'^ation. 



