GASTEROPODA. 



291 



tecfcli like helix; S. jpidris lias 50 rows of 65 teeth oacli. 

 (Thomson.) Inhabits damp places, but rarely enters the "water. 



Distribution, 155 sjiecies. World-wide. 



Fossil, 7 species. Eocene. Britain. 



Sub-genus. Omalonyx, D'Orbigny. 0. unguis, PI, XII. 

 Fig. 24. 



Shell oval, convex, translucent, spire nearly obsolete, margins 

 sharp. 



Animal large, slug-like ; shell placed on the middle of the 

 back, with the mantle slightly reflected uj)on it all round. 



Distribution, 2 species. Bolivia, Juan Pernandez. 



BuLiMrs, ScopoH. 



Etymology ? Boulimos, extreme hunger (in allusion to its 

 voracity !). 



Synonym, Bulinus, Brod. (not Adans). 



Type, B. oblongus, PI. XII., Fig. 10. 



Shell oblong or turreted ; apertui'O with the longitudinal 

 margins unequal, toothless or dentate ; columella entii'e, revolute 

 externally or nearly simple ; peristome simj)le or expanded 



Animal like Helix. B. ovatus attains a length of six inches, 

 and is sold in the market of Eio ; it 

 oviposits amongst dead leaves, the eggs 

 have a brittle shell, and the young when 

 hatched are an inch long. (See p. 44, 

 Fig. 31.) 



Sections. Odontostomas (gargantuus), 

 Beck, aperture toothed. 13 species. 

 Brazil. 



Fachyotis, Beck (Caprella, Guild.), 

 Fig. 123.* 



Partula, Fer. P. faba, PI. XII., 

 Fig. 13, Tahiti. 26 species. Asiatic, 

 ^.ustralian, and Pacific Islands, South 

 fimerica. The animal is ovoviviparous. 



Gibbus {Lyonnetianus) Montf. 



Shell hump-backed. Mauritius, 2 

 Bpecies. -fig. 12 !. 



Bulimulus, Leach. B. decollatus, PI. XII., Figs. 11 and 12. 



Shell small, lip acute. Above 300 species. England, 3 species. 



* Fig. 123. Lulimus auris-vulplna, Chemn. The great extinct larnl-snail of St. 

 Helo-iia; fr.mi a specimen presented by Clias. Darwin, Esq. Seo "Journal of a Voj-oge 



rouuiltlie World." 



02 



