422 Dr. W. C. M'Intosh on the 



Fam. 9. Littorinidae, Gray. 

 Genus 1. Lacuna, Turton. 

 Lacuna erassior, Mont. 0/:>. cit. iii. p. 344, v. pi. 64. f. 2. 

 From tangle-roots and in old shells in the laminarian region, 

 and from deep water ; not rare. 



Lacuna divaricata, Fab. Op. cit. iii. p. 346, v. pi. 64. f, 3. 

 On Fuci and laminarian blades at and beyond low-water 

 mark. The colourless variety is not uncommon ; and the same 

 may be said of var. quadrifasciata. 



Lacuna puteolus, Turton. Oj). cit. iii. p. 348, v. pi. 64. f. 4. 

 With the former at low-water mark ; less common than the 

 foregoing. 



Lacuna pallidula^ Da Costa. Op. cit. iii. p. 351, 

 V. pi. 64. f. 5&5a. 

 On the West Sands after storms, and from the laminarian 

 region. 



Genus 2. Littorina, F^russac. 

 Littorina obtusata, L. Oj). cit. iii. p. 356, v. pi. 65. f. 1 & 1 a. 

 Very common (with varieties) on stones and rocks be- 

 tween tide-marks. 



Littorina rudis, Maton. Ojp. cit. iii. p. 364, v. pi. 65. 

 f. 3, 3 a, & 3 b. 



Abundant on the rocks near high-water mark. 



Littorina litorea, L. OjJ. cit. iii. p. 368, v. pi. 65. f. 5 & 5 a. 

 Between tide-marks in vast numbers. Often eaten. 



Genus 3. Rissoa, Frdminville. 

 Rissoa parva, Da Costa. Op. cit. iv. p. 23, v. pi. 67. f. 3 & 4. 

 In great numbers on the seaweeds in the laminarian region 

 all round, especially off the East Rocks. Var. interrupta is 

 also common in shell-sand. 



Rissoa striata, Adams. Op. cit. iv. p. 37, v. pi. 68. f. 2. 

 Common under stones between tide-marks. The var. arctica 

 is the prevailing form. 



