130 MOLLUSCA FROM THE CRAG. 



strongly marked by the remains of colour, which cross the lines of growth at a 

 considerable angle, others resemble one of M. Philippi's varieties, " maculis longi- 

 tudinalibus magis minusve confluentibus." The lines of growth are very distinct, 

 and slightly elevated upon the stria?, and also between them ; and the number of 

 transverse ridges vary from six to ten. The umbilicus is generally covered, but 

 sometimes it is open. A recent specimen from the .^Egean Sea, obligingly sent to 

 me for comparison by Professor B. Forbes, appears to correspond in all essential 

 characters with my fossils, excepting that it is larger ; and the Crag shells are 

 rather more imbricated than the recent shell, which might naturally be expected 

 from the loss of the epidermis. The shell is beautifully nacreous beneath its outer 

 covering. 



12. Teochus Kicksii. Nyst. Tab. XIV, fig. 5, a— b. 



Trochus Kicksii. Nyst. Coq. foss. de Belg. p. 381, pi. 38, fig. 2, 1844. 

 — Robinsii. - - p. 382, pi. 38, fig. 3. 



Tr. Testa convexo-conica, obtusiusculd ; anfractibus 5 — 6, convexiusculis, transversim 

 tenuissime striatis ; striis impressis ; columella obliqua obsolete unidentatd. 



Shell convex or obtusely conical, thick, and strong; volutions 5 — 6, slightly 

 convex, transversely striated, with five impressed stria? ; aperture subrhomboidal ; 

 columella oblique, obsoletely toothed. 



Axis, \ of an inch. 



Locality. Cor. Crag, Sutton. 

 Red Crag, Sutton. 



A very abundant shell in the Coralline Crag. The characters which most dis- 

 tinguish this shell are the impressed stria? and rather smooth exterior ; it differs 

 but in a slight degree from T. Adansoni, and is probably a variety of that species. 

 On the young shell more especially the stria? are but few and deeply impressed. 

 The form of the shell, and its slightly convex and overhanging volution, resembles 

 the figure by M. Nyst; but his description, " undique laevigata," does not fully 

 accord with our shell, as even in my most worn and altered specimens traces of 

 stria? may be detected. 



13. Trochus tumidus. Mont. Tab. XIV, fig. 2, a — b. 



Trochus tumidus. Mont. Test. Brit. p. 280, t. 10, fig. 4, 1S03. 



GiBBUiA tumtda. Leach. MS. 1819. 



Trochus nitens. Woodward. Geol, of Norf. t. 3, fig. 10, 1833. 



— littoralis. Brown. Conch. Illust. of Brit. pi. 45, fig. 1, 4, 1827. 



— tumidus. S. Wood. Catalogue 1842. 



— — Morris. Catal. of Brit. Foss. p. 165, 1843. 



Tr. Testa convexo-conicd, obtusiusculd, crassd ; anfractibus 'tumidis, convexiusculis ; 

 suturis profundis ; superne subangulatis ; transversim tenuissime striatis ; ad basim obtuse 

 anyulatis ; aperturd subquadratd ; umbilico mediocri, scepe clauso. 



Shell obtusely or convexo-conical, strong, and variable ; whorls tumid, slightly 



