36 



1. vulgata, Lin. 



a veris — ribs but little raised, shell striated. 

 (3 costata — ribs much raised. 



'^ Patella albicosta, Marks,''"' in Brit. Mus. 

 Test. jun. Patella depressa, Pennant. 

 The animals of the two forms do not differ. 

 On all the coasts at low water ; it is called by the 

 natives " Flitter," and eaten when boiled, 



2. pellucida, Lin, 



Test. jun. " Patella biraaculata." 

 On the leaves of fuci, not common. 



3. coerulea. 



Patella coerulea, Mont. — Patella laevis, 



Penn. 



Animal cream-white, margin of the mantle waved. 



On the stalks and roots of fuci, common. Many 



British conchologists think this species identical with 



the last. Mr. Nicol, however, after a careful study 



of both species, maintains them to be distinct. 



4. tessulata. 



Patella tessulata, Midler. — Patella virginea, 

 Fleming, (not of Muller). Patella par va, 

 Da Costa. 

 See Dr. Johnston^s note on this species in the Ma- 

 gazine of Zoology and Botany, No. x. Oct. 1837- 



Dead shells, which 1 believe to belong to this 

 species, are frequent among shell-sand at Kiristal 

 near Douglas. In the Hebrides it is common, alive, 

 on small stones at low water. 



LIV. Chiton, Lin. 



