12 MOLLUSCA FROM THE CRAG. 



angles to the axis of the shell, and situate about the middle of the aperture, at the 

 lower part of the body of the shell ; the other upon the columella, midway between the 

 upper fold and the base of the aperture, and is more oblique of the two. The inner lip 

 is thick, especially at the lower part, and reflected, sometimes entirely covering the 

 umbilicus. The specimens are generally quite smooth ; but that I imagine is an acci- 

 dental circumstance, as vestiges of punctured striae, may be occasionally observed within 

 the aperture, or by the removal of the left lip, and the shell was probably, in its recent 

 state, entirely covered with striae. There is one deep ridge round the upper part of the 

 volution a little below the suture, and an incipient sinus at the upper angle of the 

 aperture. I am strongly induced to think that the inhabitant was an animal more 

 inclined to salt water than to fresh, as the specimens from the Red Crag have attained 

 to a greater size, and appear to have received their full development as associates 

 with purely marine forms. 



2. CONOVULUS MYOSOTIS (?) Drop. Tab. I, fig. 14, a b. var. /3, fig. 15. 

 AURICULA MYOSOTIS. Drap. Hist, des Moll. pi. 3, fig. 16, 17, 1805. 

 CONOVULUS BIDENTATUS. Gray. 2d edit. Turt. Man. p. 227, pi. 12, fig. 145, 1840. 

 CONOVULUS MYOSOTIS. <S. Wood. Catalogue 1842. 



C. Testa oblongo-conicd Itevigata ; spira elevatd, apice obtusiusculo ; anfractibus 8, 

 convexi usculis ; columelld biplicatd ; labro tenui, simplici. 



Shell elongated, smooth, with an elevated conical spire, and slightly obtuse apex ; 

 whorls moderately convex, with two folds upon the columella ; outer lip sharp and plain. 



Adds, rs of an inch. 



Locality. Red Crag, Sutton. 



Mam. Crag, Bramerton. Recent, Britain. 



Three specimens of this species were found by myself in the Red Crag, associated 

 with deep water, as well as more littoral species, probably carried there by the efflux 

 of the tide upon pieces of decayed wood, its favorite haunt. It has only two folds 

 upon the columella, the upper one is prominent and compressed, placed at nearly right 

 angles to the axis, the lower one is rather more obtuse and oblique. It is larger than 

 any British specimens I have seen, but is less elongated than my recent specimens of 

 C. myosotis from France, which have also three folds. Montague says of his Valuta 

 denticulata that it is a variable shell, and that specimens have sometimes as many as 

 four folds upon the columella, while others have only two, and that the outer lip is 

 sometimes denticulated within. 



The same remark is made by Dr. Gould, who considers it probable that no less 

 than six, perhaps seven, shells, figured and described under different names, are only 

 modifications of this one species, arising from age, accident, and locality. 



The Crag shell resembles, in its dentition and ovate form, the recent British species or 

 variety C. bidentatus, Gray, but is much larger, having at least twice its length, with a cor- 

 responding diameter. In the figure above referred to the artist has scarcely represented 



