30 LITTORINID.E. 



the spire. Heuce the form ranges from snbglobose to 

 ovate-acute, which last we regard as the most ordinary and 

 characteristic appearance. The shell is solid, a little glossy, 

 and its colouring is either of an uniform tint, or disposed 

 in rings. Impure scarlet, black, fulvous, or brown, 

 are the usual tints ; the two latter are often zoned with 

 numerous narrow fillets of red, or smoke-colour. There 

 are six or seven volutions divided by a fine and simple 

 suture, and terminating in a more or less acute apex. 

 They are spirally girt with densely disposed raised strise, 

 which, however, are, for the most part, much more mani- 

 fest in the young, than in the aged specimens, where the 

 surface, from abrasion, exhibits merely the intervening 

 stricc. The shelve of the whorls is considerable, that 

 is to say, they are much broader below than above ; 

 they are flattish, or plano-convex, and never much rounded. 

 The proportion of body to spire is very variable ; occa- 

 sionally they are almost equal ; in the produced form, the 

 dorsal length is in general as two to one ; in the globular 

 form, the spire hardly occupies more than a fourth of the 

 entire length. There is very often, especially in the 

 more elongated specimens, a slight disposition to refusion 

 beneath the suture of the body-whorl. The aperture is 

 large, ovate, disposed to obliquity, and more or less con- 

 tracted posteriorly. The outer lip runs at a very acute 

 angle to the body, and typically (in the adult), is more 

 arcuated anteriorly than posteriorly, the base of the shell 

 being broad in the more characteristic examples. The 

 pillar-lip is broad, plano-convex, or flattened (not retuse), 

 and white ; it is not particularly thickened at its union 

 with the outer lip : its free edge is moderately concave, 

 its inner, or attached margin, is greatly arcuated. The 

 throat is smooth, and usually of a chocolate-brown : more 



