102 PATELLA-SCUTELL ASTRA. 



on the rocks are as different as possible, the ribs and riblets being- 

 then conspicuous, and the whole shell a dull yellowish- white with 

 no trace of the scorched coloring. When dead, however, and 

 thrown on the beach this feature is conspicuous. It has many fine 

 riblets between the coarse, somewhat nodular ribs, and the margin 

 is very finely pectinated. A peculiarity of the animal is that it 

 seldom comes above low water mark, and prefers situations where 

 it is much exposed to the waves. It is very stationary, often being 

 sunk into a regular pit in the rocks, and appears to live upon the 

 fine green ulva on the rocks. It is nearly always covered, not 

 only with confervoid growths, but also nulliporse so as to quite 

 alter its shape and appearance. This often alters the height of the 

 shell, which is usually depressed, and changes the position of the 

 apex, which is usually submarginal. The interior is white and the 

 spatula not defined. 



"The animal is of uniform pale yellow at the base ; w y hite above 

 the foot, gills semi-pellucid and continued as a delicate fringe all 

 round the mantle I, however, noticed one exception where, like 

 the former species, the gills were discontinued in front of the head,, 

 mantle without tentacles ; head livid, with semi-pellucid tentacles ; 

 eyes very small and at exterior base ; buccal mass red and fleshy ; 

 cartilaginous jaws long and less tumid than most limpets ; odonto- 

 phore scarcely as long as shell ; not coiled, but bending with intes- 

 tine in two folds. Teeth closely set and not high, composed of five 

 central small curved cusps, and two tri-lobed laterals, all narrowly 

 tongue-shaped, laterals more acute. The five centrals have the 

 middle tooth often small. Teeth brown, lighter on the summit." 



(3) GROUP OF P. GRANULARIS. 



Shell oval, sculptured with numerous granose riblets, none of them 

 notably larger. Central tract of the inside and border generally 

 dark. Dist., S. Africa. 



P. GRANULARIS Linne. PL 63, figs. 80, 81, 82, 83. 



Shell solid, conical, ovate; apex in front of the middle; sculpt- 

 ured with numerous (about 50) regularly granose riblets ; the gran- 

 ules usually like small solid scales. Color dull brown, blackish, or 

 ashen, dull reddish above. 



Inside opaque-white, with a broad black or dark brown border and 

 a large reddish-chestnut central area. 



Length 58, breadth 48, alt. 26 mill. 



Cape Good Hope* 



