48.  Littorina unifasciata (n.s.)

Testa ovato-conica imperforata purpureo-albida laevigata, anfractibus convexis ultimo subangulato, apertura purpurea unifasciata.  Icon. —­

Shell ovate conical, nearly smooth, with only a few concentric ridges, and distant, scarcely impressed, very narrow, grooves; white or purplish-white outside; the whorls rather convex, last one slightly angular in front; mouth ovate; throat purple or purplish-black with a distinct broad white spiral band just below the slight external keel; inner lip purple with a deep concavity behind it; spire acute half the length of the shell; axis 8/12, diameter 6/12, of an inch.

This shell has somewhat the shape of Littorina zigzag, the Trochus zigzag of Montague, but is all of one colour externally and has a much shorter spire.

49.  Cerithium palustre, Brug.  Dict. n. 19.  Lam.  Hist. 7 66.  Strombus palustris, Gmel.  Syst.  Nat. 3521.  Number 38.  Icon.  Lister.  Conch. t. 836. f. 62. t. 837. f. 63.  Seba, 3 t. 50. f. 13. 14. 17-19.  Martini Conch. 4 t. 156. f. 1472.

50.  Cerithium ebeninum, Brug.  Dict. n. 26.  Lam.  Hist. 7 67.  Icon.  Chem.  Conch. 10 t. 162. f. 1548, 1549.  Ency.  Meth. t. 442. f. 1. a, b.

51.  Cerithium morus, Lam.  Hist. 7 75. not Brug.  Icon.  Lister. t. 1024. f. 90 ?

52.  Cerithium lima ?  Lam.  Hist. 7 77.  Brug.  Number 33.

A broken shell apparently of this species was brought home, but when a more perfect specimen is round, it may prove to be distinct from it.

53.  Cerithium perversum ?  Lam.  Hist. 7 77.

54.  Nassa fasciata, n.  Buccinum fasciatum, Lam.  Hist. 7 271.

55.  Nassa suturalis, n.  Buccinum suturale, Lam.  Hist. 7 269 ?

56.  Nassa mutabilis, n.  Buccinum mutabile, Gmel.  Syst.  Nat. 3481.  Lam.  Hist. 7 269.  Icon.  List. t. 975. f. 30.  Born. t. 9. f. 13.  Chemn.  Conch. 11 t. 188. f. 1810, 1811.

57.  Nassa livida (n.s.) Testa ovato-conica superne transverse plicata basi spiraliter striata purpureo-livida obscure castaneo bifasciata, anfractibus convexiusculis, sutura linea alba notata, labro extus marginato intus sulcato.

Icon. —­

Shell ovate conical, livid purplish-white, with one or two central, obscure brown, bands; upper whorls bluntly transversely plaited, the rest smooth, livid, except at the front part of the last, just over the groove, where it is spirally striated; the suture distinct (not channelled) marked by a white line; the inner lip distinct, raised, the outer thickened on the outer side, edge sharp, inside grooved; the throat fulvous-brown; axis one inch, diameter half an inch.

This shell belongs to the group of Nassa, but will perhaps form a distinct genus intermediate between it and Columbella, characterized by the narrow form of the mouth.  It is most nearly allied to N. olivacea, n.  (Bucc. olivaceum, Lam.) and N. canaliculata, n. (Bucc. canaliculatum, Lam.)