260 INVERTEBRATA OF MASSACHUSETTS. 



slightly perceptible angle at base ; throat deep chocolate or pur- 

 plish-brown ; operculum thin, shining, horny, brown. Length | 

 inch, breadth -^ inch, divergence 65. 



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 consider- 

 able distance from any water, 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 

 tentacula, 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 tenebrbsus, 

 the authority of Mr. Sowerby, its correspondence with the descriptions 

 and figures above cited, and the similarity of habit, render their iden- 

 tity 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 flattening 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&ta. 

 It is generally very dark^green, interrupted with dashes of buff; but 

 sometimes it is dark-chocolate color, or light-grey, and the widest va- 

 riety 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, how- 

 ever, 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 variable species than I had at first thought. 

 Some further remarks on it may be found under L. rudis. 



LITTORI'NA PALLIA'TA. 



Shell small, globular-ovate, thick, smooth ; spire small and de- 

 pressed, generally of one color, or variegated with bands and spots ; 

 aperture rounded, outer lip sharp, pillar widely flattened. 



