LITTORINA. 361 



species, known as the Turbo palliatus of Say, T. expan- 

 sus of Brown, L. arctica of MoUer, and L. limata of 

 Loven. Both Linne and Fabricius say that the animal 

 has cirrous excrescences from the foot ; and their de- 

 scriptions of the shell accord much better with those 

 given by Say and the other writers, and with typical 

 specimens of L. palliata, than with the present species. 

 The other species is common in the Clyde beds, and I 

 found it fossil also at Fort William ; it does not now 

 inhabit our seas. Middendorff considered it a variety 

 of the Turbo tenebrosus of Montagu. I am inclined to 

 regard it as intermediate between that variety (or rather 

 the YSLYiety patula) of L. rudis and L. obtusata. 



For the reasons above stated, and following Deshayes, 

 Menke, Loven, Philippi, and Middendorff in their adop- 

 tion of the name obtusata, we avoid the confusion ne- 

 cessarily incident to so many declensions of the word 

 ^' littus " or " litus '^ in this genus and its species. 

 Pulteney, Lamarck, and other authors called this species 

 Turbo neritoides ; but it is not Linnets species of that 

 name. Lamarck described it as T. retusus. 



2. L. neritoi'des"^, Linne. 



Turbo neritoides, Linn. S. N. p. 1232. L. neritoides, F. & H. iii. p. 26, 

 pi. Ixxdv. f. 1, 2. 



Body dark-grey above with a tinge of purplish-brown 

 [dusky marked with white, especially about the eyes, Philippi] : 

 head extensile and projecting beyond the foot : tentacles awl- 

 shaped and slender, very broad and bulbous at the base, light- 

 grey and lineated above with two dusky streaks : eyes rather 

 large, sessile, one on the middle of the thickened base of each 

 tentacle: foot broad, with the front corners very sHghtly 

 auricled ; sole whitish and partly furrowed in the middle. 



Shell forming a pointed cone, rather sohd, opaque, glossy 

 in the young and half-grown state, but of a duU hue when 



* Having the aspect of a Nerita. 

 VOL. III. R 



