98 



MOLLUSCA. 



Auricula. 



5. Planokbis Ei'OMPHALDS. — The Euomphalus-formcd 

 Planorbis, pi. XLN'I. fig. 23, -21. 



Planorbis Euomphalus. Sowerby, II. p. 92, pi. 140, fig. 7, 

 8, 9. Fleming, p. 279. 



Discoidal, with five or six depressed volutions, subcarinated, 

 and covered with pretty strong, equal concentric stria;, a few on 

 the superior side larger and more prominent than the others ; 

 upper side tlat ; under side rounded, and largely umbilicated ; 

 aperture subtriangular, with a slight impression from the second 

 volution. 



Fresh Water formation, Isle of Wight. 



Genus LIII.— CRASSIDORSA.— Brotin. 



Shell discoidal, involute; spire equally flat both above 

 and below, the whole of the volutions exposed ; aperture 

 circular, entire; substance of the shell thicker on the back 

 than on the inner side ; outer volution subcarinated. 



1. Crassidorsa equalis. — The Equal-sided Crassidorsa, 

 pi. XLVI. fig. 25. 



Planorbis equalU. Sowerby, II. p. 89, pi. 140, fig. 1. Ske- 

 nea equalis, Fleming, p. 314. 



Smooth, equilaterally concave, with a single, nearly obsolete 

 keel on the right side, and two on the left ; with five entirely 

 exposed, rounded volutions ; aperture orbicular, not embracing 

 the volutions; the substance of the shell thick towards the 

 outside ; whole exterior covered with somewhat obsolete, con- 

 centric striae. 



Carboniferous Limestone, Kendal. 



FAMILY IX.-COLIMACEA. 



Shell spiral ; external surface generally smooth, exhi- 

 biting only lines of growth; right margin of the aperture 

 frequently reflected outwards; animals terrestrial, with 

 cylindrical tentacula ; some species with an operculum, 

 and others devoid of one. 



Genus LIV.— AURICULA.— ZawarcA. 



Shell solid, oval or oblong-ovate, cylindrical or conic ; 

 body large; spire very small, obtuse; aperture elongated, 

 narrow, generally contracted near the centre, and rounded 

 below; outer hp thickened, reflected, or denticulated; 

 inner lip with two or three strong plaits ; outer surface 

 covered with a horny epidermis. 



1. Auricula Sedgvici — Sedwick's Auricula, pi. XLVI. 

 fig. 28. 



Auricula Sedgvici. Phillips, I. p. 129, pi. II, fig. 33. 

 Ovate; body large; spire very small, with three volutions, the 

 apex obtuse ; aporluro oval ; one plication on the pillar lip. 

 Blue Wick, Inferior Oolite, Yorkshire. 



2. Auricula obsoleta.— The Obsolete Auricula, pl. 

 XI.VL fig. 29. 



Auricula obsoleta. Phillips, 1. p. 94, pl. 2, Cg. 40. 



Suborbicular ; body large ; spire small, with two volutions, 

 the apicial one rather obtuse; entire surface covered with a 

 numerous series of spiral, regular punctated stria;. 



Speeton Clay at Speeton. 



3. Auricula pvramidalis. — The Pyramidal Auricula, pl. 

 XLVI. fig. 32, 33. 



Auricula jj^raiuidalis. Sowerbv, l\'. p. 109, pl. 379, fig- 

 1,2. 



Ovate, smooth ; body large ; spire small, pyramidal, consist- 

 ing of five or six narrow, well defined volutions, rounded above, 

 with an acute apex ; aperture elongated, narrow above, occupy- 

 ing half the length of the shell; outer lip sharp; inner lip some- 

 what thickened, with two rather contiguous, slightly obtruding 

 plaits upon the columella, and a small umbilicus behind it. 



4. Auricula incrassata The Thickened Auricula, pl. 



XLVI. fig. 44, 45. 



Auricula incrassata. Sowerl^', II. p. 143, pl. 163, fig. 1, 2, 

 3. Auricula ringens, Parkinson, Org. Rem. III. p. 84, pl. 5, 

 fig. 4. 



Ovate, ventricose ; body very large ; spire small, with three 

 well rounded volutions, the apicial one very minute ; aperture 

 smooth within, oblong, semilunar, contracted above, wide below; 

 outer lip very broad, greatly thickened behind, with very strong 

 longitudinal lines of growth, instead of sulci, slightly reflected in 

 front ; pillar lip broad, thick, with three plaits ; whole surface 

 covered with numerous, regular, spiral ribs, the intervening fur- 

 rows furnished with longitudinal, regular, sharp, elevated, wide- 

 set stria>, dividing them into small, oblong, rectangular cells, 

 which can only be distinctly seen by the aid of a strong lens. 



London Clay at Blackdown. 



5. Auricula turgida. — The Swollen Auricula, pl. XLVI. 

 fig. 46, 47. 



Auricula turgida, Sowerby, II. p. 143, pl. 163, fig. 4. 



Siibovate, glossy ; body large, nearly orbicular ; spire short, 

 with three slightly rounded, but not deeply defined volutions, 

 the apex acute ; aperture oblong, a little oblique, contracted 

 above; outer lip thick, smooth internally at the edge, and some- 

 what elevated and contracted in the middle ; inner lip rather 

 broadly and thickly reflected on the columella, with two thin, 

 prominent folds; surface covered with fine, regular, spiral stria;. 

 Length somewhat more than an eighth of an inch. 



London Clay at Highgate Hill, London. 



6. Auricula ventricosa. — The Ventricose Auricula, pl. 

 XLVI. fig. 34, 35. 



Auricula ventricosa. Sowerby, V. p. 99, pl. 465, fig. 1. 



Subovate ; body large, inflated ; spire conical, of medium 

 length, with four well rounded volutions, slightly flattened 

 above, and acute at the apex ; aperture elongated, contracted, 

 narrower above ; outer lip much thickened, a little reflected on 

 the edge ; inner lip with a broad and thick callous, and three 

 elevated, sharp plaits; base notched; surface with pretty strong, 

 regular, spiral stria;. Length three-eighths of an iiiili. 



A Crag fossil from near Ipswich. 



7. Auricula Buccinea. — The Buccinum Auricula, pl. 

 XLVI. fig. 38, 39. 



Auricula Buccinea. Sowerlty, V. p. 100, pl. 465, fig. 2. 

 f'^oluta Buccinea, Brocchi, p. 319, pl. 4, fig. 9. 



Suliovate, smooth; body ventricose; spire of medium length, 

 with four slightly rounded volutions, terminating in an acute 



