GASTEROPODA. 77 



upon some of the Older Tertiary Pleurotoma, and I believe that colour is preserved upon 

 some of the older Secondary Fossils. So far as the uncertainty which always attaches 

 from the resemblance to this species which other species, when fossil, may from decortica- 

 tion put on, will allow me to say, N catena seems common in the Fluvio-marine Crag 

 of Bramerton, and in the Chillesford bed at Horstead and Coltishall, but rare in the 

 Lower Glacial sands, and is common in the young state in the Middle Glacial of Hopton 

 Billockby. I have not seen it from the Post-Glacial beds of East Anglia. 



Natica pusilla? Say. Supplement, Tab. IV, fig. 9. 



Natica pusilla, Smj. Journ. Acad. Nat. Sci. Phil., ii, p. 257, 1822. 



— — Binney. Gould. Inv. Massach., 2nd ed., p. 344, fig. 613, 1870. 



Locality. Coralline Crag, near Orford. 



The above represents a shell I have lately obtained, but, like the generality of speci- 

 mens of the Crag Natica, the glossiness of the exterior is gone. I have given it the above 

 name with doubt, as my shell differs in some respects from the existing one. On 

 comparing my specimen, it seems to have rather more convex volutions than the recent 

 pusilla, and the pad over the umbilicus larger and more extended in the Crag shell. It 

 resembles somewhat Nat. occulta, Desh., 'Des. An. sans Vert./ PI. LXVIII,figs. 11 — 13, 

 and it appears intermediate between the two, as if the Crag one descended from the 

 Paris basin shell with alteration, and the recent species from the Crag one with still further 

 alteration. I feel much disposed to consider it specifically distinct, and to call it 

 N occultata, but having only two or three specimens, and those with the exterior not 

 perfect, I have preferred giving it the above name. 



Natica catenoides, S. Wood. Crag Moll., vol. i, p. 141, Tab. XVI, fig. 16, Supple- 

 ment, Tab. IV, fig. 13 a, b. 



Localities. Red Crag, Waldringfield, Sutton, and Walton. Chillesford bed, Easton 

 Bavent. ? 



The shell represented in fig. 13 of Supplement, Tab. IV, was obtained at 

 Waldringfield by Mr. Canham, which being much larger than the one represented in 

 ' Crag Moll./ 1 thought it desirable that it should be figured; especially as considerable 

 uncertainty has existed, and, indeed, still exists, respecting the correct appropriation of 

 this Red Crag shell. The late Edward Forbes considered it identical with N. ylaucina 

 (catena), 'Mem. of the Geol. Survey,' 1846, p. 430; while in the ' Brit. Moll./ vol. iii, 

 p. 306, 1853, the authors refer this Crag shell to Nat. sordida. Again, M. Thuden has still 

 more recently placed it as a doubtful synonym with Nat. nitida ('Om. de J. Bohus. 

 Postplioc. eller. glac. format./ p. 56, 1866). I cannot say that I agree with any of these 



