XXI 



it is only mentioned here because Prof. Haldeman 

 adopts it as a generic name in a late paper on the 

 classification of these shells.* 



For the same reason we do not adopt the genus 

 Ambloxis described in the American Monthly Mag- 

 azine, p. 355, 1818 : — 



"Univalve. — Shell thick ohoval, mouth oval, rounded at the 

 base, obtuse above, with a thick appendage of the lip, colu- 

 mella flexuose, a small rugose umbilic." 



This, the only description, would apply equally 

 well to a Paludbia, Anculosa or a Goniobasls of Lea, 

 and in 1831 (Enum. and Account), although he 

 renders it plain that he intended the latter, still he 

 does not adopt the name for his species there de- 

 scribed, and seems disposed to doubt the value of 

 his former division. 



The three following genera were published in 

 Journal de Physique, Bruxelles, tome 88, p. 423 et 

 seq. : — 



'•'■ EUip stoma ^ Raf. — Shell thick, oval, obtuse. Mouth ob- 

 lique, narrow, elliptic, lips thickened, united and obtusely 

 deciirrent posteriorly. A narrow, ol^long umbilicus, half cov- 

 ered by the interior lip. Animal unknown. Fluviatile genus 

 of 4 species, E. gibbosa, E. vittata, E. zonalis and E. mar- 

 ginula. 



"From the Ohio, Mississippi, etc." 



'•'• Oxytrema, Raf. — Differs from Pleurocera by an oval ob- 

 long or ventricose shell, less number of whorls, the last form- 

 ing nearly the whole ; mouth sharp on both sides, and anteri- 

 orly prolonged into a long, sharp point. 3 fluviatile species." 



'•'■ Campeloma, Raf. — -Shell oval; mouth oval, base trun- 

 cated, lip reflected, united in a posterior point. No umbilicus. 

 Animal unknown. 1 have only one species, found in the Ohio, 

 — C. crassnla. Four whorls of the spire reversed, apex acute, 

 shell thick, mouth more than half the total length." 



Messrs. H & A. Adams, with very doubtful pro- 

 priety, refer this genus to Mdunopsis. Prof. 8. S. 

 Haldeman, in an article on Mollusca, contributed by 

 him to the American edition of Heck's Iconographic 

 Encyclopaedia, ii, p. 84, remarks that : — 



• Proceed. Acad. Nat. Sciences, p. 274, September, 1863. 



