128 MOLLUSCA FROM THE CRAG. 



Axis, \ of an inch ; diameter, | . 



Locality. Red Crag, Sutton. 



This species is at present rare in my cabinet. It appears to differ from T. mille- 

 granus, the species to which it approaches nearest, in having the ridges granulated ; 

 but it is without the imbricated character of that species, and the edges of the 

 volutions are not so sharp and angular as in that shell, or in T. miliaris ; the volu- 

 tions, also, are not so flat. It differs from any of the specimens of T. exiguus that I 

 haveseen,in having the outer edgeof the volutions less angulated, and in wanting the 

 distinct basal ridge of that shell, and moreover its sides are less flat. Our shell has 

 two or sometimes three prominent granular ridges at the lower part of the volution. 

 It is more finely and regularly granulated than the young of T. subexcavatus, for 

 which it might otherwise be mistaken. 



Sect. b. UMBILICATED. 



9. Teochus villicus (?)„ Phil. Tab. XIV, fig. 4, a— b. 



Trochus villicus. Phil. En. Moll. Sic. vol. ii, p. 152, t. 25, fig. 14, 1844. 



Tr. Testa conicd, obtusiusculd, cr asset ; anfractibus quinque, planulatis, superne sub- 

 angidatis ; transversim cingulatis, cingalis 5 — 7, inaqualibus ; anfractu ultimo angulato ; 

 columella obsolete unidentatd ; umbilico parvo. 



Shell conical, somewhat obtuse, thick and strong, with about five volutions, 

 rather flat, and projecting slightly at the upper part, ornamented with 5 — 7 un- 

 equal ridges, imbricated by the elevated and reflected lines of growth ; base of 

 volution angulated and striated ; columella with an obsolete tooth ; umbilicus very 

 small. 



Axis, |- of an inch. 



Locality. Cor. Crag, Sutton. 



Red Crag, Sutton. Recent, Mediterranean. 



I have about half a dozen specimens of this shell in my cabinet from the Red Crag, 

 which appear to resemble what M. Philippi has considered a new species ; and in 

 his examination of the recent shell he may have detected more decided characters 

 for its establishment ; but, judging from my fossils alone, I consider it only a variety 

 of T. Adansoni. My specimens have but a very small umbilicus, which may arise from 

 the position of the volutions being a little more erect ; in other respects it corre- 

 sponds so closely with his figure and description that it may be considered the 

 same. From five to seven large and obtuse irregular-sized ridges cover the upper 

 side of the volution, and there are about the same number on the base, but rather 

 smaller and more regular ; the ridges are all crossed by erect and slightly reflected 

 lines of growth, which are most distinct between the ridges. 



