Natica. 



MOLLUSCA. 



89 



instances increases so as to cover it, in others it is very 

 small, and in a few instances nearly obsolete, so much 

 so, as to be hardly perceptible as an umbilical opening ; 

 operculum testaceous in some species, and horny in 

 others. 



Grayish 



I. 



Natica, pi. 

 p. 19, pi. 5, 



effuse; outer lip sharp-edged, smooth within; columellar Found in the London Clay. 



lip transversely oblique, destitute of teeth, generally 5. Natica cirriformis. — The Cirrus-shaped Natica, pi. 



thickened, and sometimes with a coating of enamel XLIII. fig. 20, 21. 



spread thickly over the umbilicus ; umbilicus usually Shell subglobose ; spire rather short, consisting of three well 



large, having a spiral callosity within, which in some rounded, but somewhat depressed volutions, the apicial one 



much blunted; body rather flattened above; aperture small, 

 sublunate, rounded both above and below ; pillar lip thickened, 

 with a central sinus ; umbilicus very large, intruding upon the 

 columella, destitute of a spiral ridge, and exposing the volutions 

 internally as far as the apicial one ; behind the pillar lip some 

 strong, elevated, nearly equidistant, longitudinal ridges. 

 Found in the Suffolk Crag. 



6. Natica patula.— The Open Natica, pi. XLIII. fig. 

 22, 23. 



Natica patula. Sowerby, IV. p. 99, pi. 373, three lower 

 figures. Fleming, p. 32 L 



Shell slightly ovate; body very large, flattened in front; spire 

 very short, and much depressed, hardly rising above the general 

 surface of the body, consisting of four very small volutions, ter- 

 minating in an acute apex; aperture sublunate, rounded both 

 above and below ; pillar lip considerably thickened ; umbilicus 

 large, and partly filled by a callus, with a smaller one, forming 

 a spiral ridge within; general surface smooth, with very minute, 

 concentric strias, and rather obsolete Hnes of growth. 



Found at Ipswich, in the Suffolk Crag. 



7. Natica cincta The Girdled Natica, pi. XLIIL 



fig. 25. 



Natica cincta. Phillips, I. p. 101, pi. 4, fig. 9- 

 Shell ovate ; spire depressed, consisting of three volutions, 

 flattened above ; body with a large obliquely flattened space 

 above, with a subcarinated edge ; aperture sublunate, with a 

 sharp outer lip, and a moderately thick columellar glazing; um- 

 bilicus rather small; outer surface smooth, with distinct lines of 

 growth ; the body invested by a spiral fillet or band. 

 Found in the Coralline Oolite at Malton. 



8. Natica ampliata. — The Ample Natica, pi. XLIII. fig. 

 26, 27. 



Natica ampliata. Phillips, II. p. 224, pi. 14, fig. 21 and 24. 



Shell hemispherical ; body very large, much inflated ; spire 

 very small, sunk behind the outer lip, and consisting of two 

 much depressed, ill defined volutions ; aperture ample ; outer 

 lip much expanded; columellar lip plane; whole surface covered 

 with small, equidistant, filiform, longitudinal striae. 



Found in the Mountain Limestone at Bolland, and in Nor- 

 thumberland. 



9. Natica plicistria. — The Plicistriate Natica, pi. XLIII. 

 fig. 32. 



Natica plicistria. Phillips, IL p. 225, pi. 14, fig. 25. 



Shell oblong-ovate; body large, smooth; spire small, sub- 

 conic, consisting of three plicistriate volutions, their superior 

 edges being obliquely flattened, as well as that of the body. 



When the shell is old, the flat space becomes concave. 



Found in the Mountain Limestone of Bolland, Bristol, Nor- 

 thumberland, Kirby Lonsdale, and Kildare, Ireland. 



10. Natica adducta The Close Natica, pi. XLIII. fig. 



33 and 41. 



Natica adducta. Phillips, I. p. 123, pi. 9, fig- 30, and p. 

 129, ph 11, fig. 35. 



1. Natica glaucinoides The 



XLIIL fig. 30, 31. 



Natica glauciiioides. Sowerby, Min. Conch, 

 three upper figures. Fleming, Brit. An. p. 320. 



Shell semiglobular ; body very large, inflated, slightly flat- 

 tened, and a little concave above ; spire small, consisting of 

 four rounded, rapidly decreasing volutions, terminating in a 

 pointed apex; umbilicus large, simple, while in some specimens 

 it is partly closed, by a slight elongation of the glazing of the 

 pillar lip ; surface very glossy, of a light grayish-brown colour, 

 with indications of darker bands. 



This shell strongly resembles N. glaucina, but its spire is more pro- 

 duced than in that species, the inner lip is also stronger, and liable to 

 become callous over the umbilical region. 



Found in the London Clay at Highgate, and in the Suffolk 

 Crag. 



2. Natica similis The Similar Natica, pi. XLIII. fig. 



28, 29. 



Natica similis. Sowerby, I. p. 20, pi. 5, two middle figures. 

 Fleming, p. 320. 



Shell smooth, somewhat rhomboidal, or slightly ovate ; spire 

 very short, consisting of three or four depressed volutions, the 

 apicial one obtuse ; aperture sublunate, longitudinal ; outer lip 

 not much expanded, and plain ; inner hp thickened, bilobate, 

 dividing the umbilicus, which is deep, and with a flattened area 

 at its lower side. 



Found in the London Clay at Highgate, and also at Bognor. 



3. Natica discrepans The Differing Natica, pi. XLIII. 



fig. 24. 



Natica glaucinoides. Sowerby, V. p. 126, pi. 499, fig. 4. 



Shell ovate, smooth, and glossy ; spire very short, consistmg 

 of four depressed volutions, with the apicial one obtuse ; aper- 

 ture large, sublunate, with the outer lip considerably expanded, 

 and plain at the edge ; pillar lip broadly thickened upon the 

 columella above, but narrowed below; umbilicus deep and wide, 

 but suddenly contracting internally. 



This shell differs from the IV. glaucinoides, in its more expanded 

 outer lip, and in the aperture being larger in proportion to the size of 

 the shell. 



Found in the Suffolk Crag, and at Bramerton, Norfolk. 



-The Sigaritus-formed Natica, pi. 

 p. 126, pi. 479, fig. 3. 



4. Natica sigaratina.- 

 XLIIL fig. 18, 19. 



Natica sigaratina. Sowerby, V. 

 Fleming, p. 321. 



Shell smooth, greatly depressed ; spire small, with three ill 

 defined volutions, hardly rising above the body ; aperture ovate, 

 obliquely curved, and contracted above ; outer lip even ; thick- 

 ening on the pillar narrow ; umbilicus large, nearly filled vvith a 

 lenticular callus, a small portion, however, is always open. 



