242 PYRAMIDELLIDiE. 



be so in this. Our proposed arrangement, then, is to 

 retain the name Chemnitzia for the ribbed shells without 

 tooth ; Odostomia for such as are smooth or rarely pli- 

 cated, and if solid or enamelled, always toothed ; and 

 EuUmella for those with a smooth enamelled surface, and 

 no tooth on the straight columella. The apex in Chem- 

 nitzia seems, almost always, to consist of more coils than one. 

 Although existing Chemnitzia are all small shells, there 

 are fossil species belonging to this genus of considerable 

 dimensions. During the palaeozoic epoch, shells very nearly 

 connected with this group lived, and during the oolitic 

 epoch characteristic forms of it were not uncommon. 

 Those now in being are often of extreme elegance of 

 form and richness of sculpture. For the most part they 

 inhabit the laminarian zone in gravelly or stony places, 

 but some of them range to considerable depths, even to 

 one hundred fathoms and below. The genus appears in 

 the main to belong to temperate climates. 



0. ELEGANTISSIMA, MoutagU. 



Slenderly-turreted, uniform white, with from nine to thirteen 

 flattened, or but little ' convex, whorls ; ribs strong, simple, ob- 

 lique, close, numerous (at least fifteen) ; no spiral sculpture. 



Plate XCIII. fig. 1,2. 



rurho ladeus, Linn. Syst. Nat. ed. 12, p. 1238.? 



„ eleganiissimus, Mont. Test. Brit. vol. ii. p. 298, pi. 10, f. 2 ; Suppl. 

 p. 124. — TuRT. Conch. Diction, p. 209.— Dill w. Re- 

 cent Shells, vol. ii. p. 856. — Wood, Index Testae, 

 pi. 31, f. 97. 

 „ acutus, DoNov. Brit. Shells, vol. v. pi. 179, f. 1. 

 Helix elegantissima, Maton and Rack. Trans. Linn. Soc. vol. viii. p. 209. 

 TurriteUa „ Fleming, Brit. Anim. p. 303. — Potiez and Mich. Gal. 



Douai, Moll. vol. i. p. 281. 

 Melania Campaticllce, Philipm, Moll. Sicil. vol. i. p. 15(), pi. 9, f. .5. 



„ ekffantissima, FoiinES, MaLic. Mon. p. 15. 

 Partlienia „ Lowe, Proc. Zool. Soc. 1840, p. 41. 



