LITTORINA. 307 



of the shell; aperture less than one half, nearly circular ; outer lip 

 thin and sharp, yellowish, thickening a little as it meets the fiat- 

 toned and slightly everted pillar lip, forming a slightly per- 

 ceptible angle at base ; throat deep chocolate or purplish- *'°' ^'^' 

 brown ; operculum thin, shining, horny, brown. Length, 

 one half inch ; breadth, seven twentieths of an inch ; diver- 

 gence sixty-five degrees. 



This species is found about sluggish waters, wharves, 

 bridges, ditches, and pools upon marshes, on the mud, 

 and climbing culms of grass. It is often found on the marshes at 

 a considerable distance from any Avater, but I do not recollect that 

 I have ever found it at the open sea, where it was liable to sustain 

 any violence from currents or the surf. 



The animal has a dark olive head, and an olive stripe on the ten- 

 tacula, from the eye ; the sides of the foot are beautifully lined with 

 the same, and it is very sluggish in its movements. It lives a week 

 or more after being removed from the water. 



Actual comparison of our shell with the British Turbo tenebro- 

 sus, the authority of Mr. Sowerby, its correspondence with the de- 

 scriptions and figures above cited, and the similarity of habit, ren- 

 der their identity quite certain. 



Its distinctive points are, the elevation of the spire, formed of 

 very tumid whorls, abrupt and not sloping at the suture ; the short, 

 nearly circular mouth, with its thin, yellow lip, the very partial flat- 

 tening of the inner lip producing a very slight angular curve in 

 front ; the dark purplish-brown interior ; and above all, the olive- 

 colored head and markings of the animal. 



Its varieties of form are not great, consisting in the greater or less 

 elevation of the spire. In coloring it is not so variable as L. palli- 

 ata. It is generally very dark green, interrupted with dashes of 

 buff; but sometimes it is dark chocolate color, or light gray, and 

 tlie widest variety I have seen is a dark brown, with one, two, or 

 three bands of white. In sculpture there is considerable variation, 

 consisting in the deeper or more superficial revolving grooves. In 

 most cases, however, there are none distinctly visible to the naked 

 eye. 



The limits of the species are not very readily declared ; but I now 

 suppose it to be a less varial)le species than I liad at first thought. 

 Some further remarks on it may be found under L. rud'u. 



Halifax ( Willis) ; whole Canadian coast (^Bell) ; James's Bay, 

 fifty-two degrees, ten minutes (^Drexler}. 



