SUCCINEID^. 87 



than a sing. Xo exact generic characters are given. 0. Sys- 

 mondii, Gray. Gaboon, Africa. 



EUMELUS, DEBOCERAS, ZILOTEA, URCINELLA, TESTACINA, LIMACIAS, 



Rafinesque. All unrecognized genei'a of slugs. 



PARMULA, scuTELLiGERA = Larvae of insects — Gray, Cat. Brit. 

 Mus., 161. 



f f Elasmognatha. 



Jaw with a superior quadangular accessory plate. 



Family SUCCINEID^. 



Shell oblique, sometimes flattened, paucispiral, very thin, 

 transparent. 



Inferior tentacles but slightly developed or wanting ; jaw with 

 a median quadrangailar accessor^^ piece, projecting upwards 

 (xiii, 63) ; central tooth tricuspid, same size as the laterals which 

 are bi- or tricuspid, marginals narrow at base, multicuspid. 



SucciNEA, Drap., 1801. 



Syn.. — Cochlohydra, Fer., 1819. Neritostoma, Klein, 1153. Lu- 

 cena, Oken, 1815. Amphibina and Aniphibulina, Hartmann, 1821. 



Distr. — 200 sp., world-wide ; subaquatic, living in damp places, 

 near the margins of streams. Fossil ; Eocene — . 



Shell oval, very fragile and transparent ; spire short ; the 

 whorls few, and very rapidly enlarging ; apei^ture oval ; outer lip 

 thin, not reflected, united below by a broad curve with the thin, 

 smooth columella. 



Animal large, usually barely retractible within its shell ; ten- 

 tacles short and thick, the inferior pair inconspicuous ; foot broad. 



TAPADA, Studer, 1830. (Succinea, restricted.) Whorls well- 

 rounded, with impressed sutures. S. obliqiia, Say (c, 32). U. S. 



BRACHYSPiRA, Pfr., 1855. Shell ovate, inflated ; spire very 

 short, acuminate; last whorl flattened, scutiform; aperture 

 large, angulated. S. ovalis, Gould. S. putris, Linn, (c, 33). 



TRUELLA, Pease, 1811. Shell elongate, slender; aperture con- 

 tracted behind. 3 sp. Polynesia. S. procera, Gld., etc. 



PELTA, Beck, 1831. S. Gumingii,'Beck. Ins. Juan Fernandez. 



HELisiGA, Lesson, 1829. Shell ovate-ventricose ; spire very 

 short ; aperture wide, patulous ; peristome acute. Eye-peduncles 

 short, cylindrical, swollen at the base ; tentacles short, rudi- 

 mentary. S. Sancta-JSelense, Lesson. St. Helena. 



Omalonyx, d'Orb., 1841. 

 Distr. — 5 sp. West Indies and Brazil. 0. unguis, d'Orb. 

 (c, 36). 



