128 UNIVALVES PATELLA. 



dica, P. sanguinolenta and P. testudiiiaria; the latter is 

 rather a rare species, and generally has its interior of a 

 silvery hue. The P. compressa is remarkable for its nar- 

 row and lengthened form, which gives it the appearance 

 of having been squeezed or pinched. 



The last division of the Patella inc' "^7,s the perfor- 

 ated species: the principal are the P. fissuid, P. Grseca, 

 P. nimbosa, P. Jamaicensis, P. Caflfra, P. perforata, and 

 P. personata; the latter, when in fine preservation, is consi- 

 dered a rarity ; it grows to a considerable size, and is 

 found at the Falkland Isles and the Straits of Magellan. 



The P. mytiliformis very much resembles a Mytilus; it 

 is from the Ferroe Islands. 



The P. Hungarica is sometimes found in a fossil state, as 

 is also the P. echinata in the neighbourhood of Crignou. 



The Patellar; are usually found adhering by their base 

 to rooks, stones, fuci, and other marine substances, from 

 which they are with much difficulty removed. They in- 

 habit the Indian, Southern, European, Northern, and 

 Mediterranean seas; the American and Indian islands; 

 the Atlantic, and the shores of China, Greenland, and 

 Iceland. 



The Patellae derive their name from their resemblance 

 to a little dish or bason reversed. 



PATELLA.— Zm^ef. 



A. — Having an internal lip; shell entire. 



Equestris — Cup 8^ saucer. Fornicata — Slipper. 



Neritoidea — Chambered. Aculeata — Spiny-ribbed. 



Sinensis — Chinese bonnet. Trochiformis — Trochus- shaped. 



Porcellana — IVhite spotted. Auricula — Ear-shaped. 



