78 
MARINE FAUNA OF ST. ANDREWS. 
Littorina litorea , L. Op. cit. iii. p. 368, v. pi. 65. f. 5 & 5 a. 
Between tide-marks in vast numbers. Often eaten. 
Genus 3. Rissoa, Freminville. 
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. 
Rissoa soluta, Philippi. Op. cit. iv. p. 45, v. pi. 68. f. 7. 
Occasionally in deep water and in shell-sand. 
Rissoa semistriata , Mont. Op. cit. iv. p. 46, v. pi. 68. f. 8. 
Fi*om deep water and in shell-sand ; not common. 
Genus 4. Hydrobia, Hartmann. 
Hydrobia ulvce , Pennant. Op. cit. iv. p. 52, v. pi. 69. f. 1. 
In great abundance in the brackish pools near the mouth of 
the river Eden. 
Fam. 11. Skeneidae, Clark. 
Genus 1. Skenea, Fleming. 
Rkenea planorbis, Fab. Op. cit. iv. p. 65, v. pi. 70. f. 1. 
Common in rock-pools amongst Ceramium and other algae. 
Genus 2. Homalogyra, Jeffreys. 
Homalogyra rota , Forbes & Hanley. Op. cit. iv. p. 71, 
v. pi. 70. f. 3. 
Jn shell-debris from the West Sands. Dead. 
