GASTEROPODA. 29 



2. Nassa incrassata. MilU. Tab. Ill, fig. 4. 



Tkitonium incrassatdm. Mull. Prod. No. 294G, 17/3. 

 BucciNUM MACULA. Moiit . Test. Brit. p. 241, t. 8, fig. 4, 1803. 



— AscANiAS. Brug. ex Phil. En. Moll. Sic. vol. ii, p. 188. 



— ASPERULUM. Broc. t. 5, fig. 8, 1814. 

 Nasa incrassata. Flem. Brit. An. p. 340, 1828. 

 Nassa incrassata. S. Wood. Catalogue 1842. 



N. Testa ovafo-conicd, subtiirrifd ; spird acutd ; hnc/itudhialiter costatd ; trcmsvenim 

 anguste striatd ; anfradibus 6 — 7 convexis, tumidis ; aperturd subrotundd ; labro in- 

 crassata, varicoso, intiis deiiticulato. 



Shell rather small, ovato-conical, subturreted, longitudinally costated, and finely 

 striated transversely ; whorls 6 — 7 convex, tumid ; aperture subcircukr, with a 

 thickened outer lip, denticulated within. 



Axis, 5 of an inch, nearly. 



Locality. Cor. Crag, Sutton. 



Red Crag, Sutton. Recent, Britain. 



Very scarce in the lower formation ; more abundant in the Red Crag. My specimens 

 seldom exceed | of an inch in length. The costse m the last volution vary from 12 — 15, 

 with 12 — ^15 threads along the whorls, and carried over the ribs. Denticulations 

 within the lip, lower one the most produced, with a distinct ridge on the opposite 

 side of the canal at the base of the columella, contracting the entrance to the canal, 

 with a prominent tooth upon the body whorl, near the upper part of the aperture. 

 This appears to correspond with the recent species in every character except its size, 

 the recent British specimens being generally larger. 



3. Nassa granulata. /. Sow. Tab. Ill, fig. 3. 



BncCINUM GRANULATUM. J. Sow. Min. Con. t. 110, fig. 4, 1815. 



— Nyst. Coq. foss. de Beige, p. 575, pi. 43, fig. 11, 1844. 



Nassa granulata. S. Wood. Catalogue 1842. 



N. Testd ovato-conicd, turritd, apice acuto ; anfractibus convexis, longitiidinaliter costatis, 

 transversim striatis ; striis elevatis granulatis ; aperturd subrotundd ; Jnbro incrassato intus 

 dentato ; labio superne unidentato. 



Shell ovato-conical, with an elevated and acute spire ; whorls convex, longitudinally 

 costated, and decussated by coarse and elevated striae ; aperture subcircular, with a 

 reflected left lip and thickened margin denticulated within. 



Axis, I of an inch. 



Locality. Cor. Crag, Sutton. 

 Red Crag, passim. 



Ver}"^ abundant in the Red Crag, but rare in the Coralline. In shape it much re- 

 sembles the preceding species, but the striae, or rather ridges, are fewer and larger, and 

 carried over the costae, which give it a granulate appearance, and regularly decussate 

 the exterior. The outer lip has fewer teeth. The tooth on the body whorl forms an 



