235 

 Terebratula continued. 



depressa. . oblong ; transversely dilated, contracted and obtuse 

 upwards ; with smooth concentric striae ; beak produced, 

 not incurved ; foramen large. . St. Saturin. 



avails. . transversely and superiorly dilated ; with concentric, 

 smooth striae ; beak incurved. 



numismalis. . depressed, subrotund, smooth ; a sinus in the 

 upper part of each valve ; distant concentric striae ; beak 

 short ; foramen very small. 

 This shell, though round, shows five angles. 



umbonella. . elongated, turgid, transversely compressed ; above 

 obtuse ; smooth, with a raised umbo ; beak incurved. . 

 Montigny. 



diyona. . elongated, subgibbous, grooved upwards, smooth, ter- 

 minating in two angles ; beak raised and incurved. . near 

 Bath. 



This species generally shows very plainly a beautifully punc- 

 tated surface ; a similar surface is observable in several of 

 the smooth species. 



deltoidea. . compressed, transversely dilated, triangular, smooth; 

 margin straight in the upper part, winding in the middle. 



triangulus. . elongated, triangular, smooth ; the lower valve re- 

 flected on the upper, with a groove on the margin. 



cor. . cordiform, subglobose, a deep sinus in the upper part ; 

 decussated with delicate striae. 



birostris. . subglobose, smooth ; contracted upwards, sinuated 

 in the middle ; sinus with two angles, margin not plicated. 



ampulla. . subrotund, inflated, antiquated ; upper margin ob- 

 scurely biplicated. . Italy. 



carinata. . subquadrangular, smooth; lower valve rather flattish ; 

 upper valve diedral, the two surfaces divided by a longitu- 

 dinal keel, formed by their union at an obtuse angle. 



concava. . small, lower valve flat ; upper one larger and concave, 

 with concentric striae. . Meudon. 



semiglobosa. . elongate, ovate, tumid, very smooth ; umbo raised, 

 margin entirely without plicae. . Warminster. 



piinctata. . oblong, subdepressed, upward biplicated, with con- 

 centric striae ; and with minute points disposed in undu- 

 lating lines. 



phaseolina. . small, subcompressed, subrotund, with concentric 

 striae ; upper margin subbiplicated, beaks short. . Mons. 



ovata. . ovato-oblong, subcompressed, smooth ; with distant 

 concentric striae ; beak produced. . Heytesbury. 



biplicata. . subrotund, subglobose, smooth, biplicated upwards ; 

 concentric striae ; beak incurved ; plane of the foramen 

 horizontal. . Cambridge. 



bisinuata. . subrotund, subdepressed, antiquated, smooth, up- 

 wards biplicated ; beak produced, not incurved ; plane of 

 the foramen inclined upon that of the valves. . Grignon. 



Kleinii. . ovate, depressed, subantiquated, smooth, biplicated 

 upwards ; finely and closely punctated ; beak incurved. 



