SCALARIA. 211 



S. GRCENLANUICA. 



Ribs separated by spiral ridges. 



Plate LXX. f5g. 5, 6. 



Turbo clathrus Groenlaudkus, Chemn. Conch. Cab. vol. xi. p. 155, pi. 195, 



f. 1878, 1879. 

 Scaluria planicosta, Kiener, Coquil. Vivant. Scalaria, p. 18, pi. 7, f. "21. 



„ subulata, Couthouy, Boston Jl. Nat. H. vol. ii. p. 93, pi. 3, f. 4. — 



Dekay, New York Fauna, Moll. p. 125, pi. 6, f. 125. 

 „ Groinlandica, Gould, Invert. Massach. p. 249, f. 170*. — Se.4Rles 



Wood, Crag. Mollusca, p. 90, pi. 8, f. 11 (fossil). 

 „ Vreenlandica, Sovverby, Thesaur. Conch, p. 101, pi. 34, f. 105, 110. 

 „ simiiis, J. Sowerby, M. Conch, pi. 16 (fossil). 



As only a fragment or two of this strongly featured 

 Scalaria has been taken in Great Britain, we have been 

 compelled to have recourse to foreign specimens, for our 

 drawing and description of this boreal species. The shell 

 is of a somewhat produced turreted form, strong, almost 

 opaque, or only a little translucent, of an unitbrm chalky 

 white, livid brown or bluish white tint, and never either 

 zoned or variegated by coloured markings; the ribs, however, 

 are often of a paler hue in the more lurid examples. From 

 eight to fifteen broad, simple, stout, flattened, and not much 

 slanting ribs, of which one or two on the last few whorls 

 are somewhat bigger than the rest, traverse the surface in 

 a longitudinal direction ; on the upper turns, however, 

 they are mere lamellae. Their intervals, which, considering 

 the breadth of the ribs, are rather narrow than otherwise 

 (yet always much wider than the cross-bars themselves) 

 are occupied by from six to eight spiral ridges, that 

 are rounded, rather depressed, and closely packed. The 

 terminal one upon the body is bigger than the rest, and 

 running from the posterior end of the aperture, leaves 

 somewhat lai-ger intercostal intervals, than those allowed 



