The Key-hole Limpets 



Strongly ribbed, with about a dozen larger ribs evenly distributed. 

 The colouring is grayish green, sometimes tinted with pink or 

 shaded with purple and brown. The key-hole is small and 

 circular, with a thick green callus inside. Length, ij inches. 



Genus LUCAPINA, Gray 



Shells large, thick, flattened, oblong-oval, finely ribbed and 

 cross-banded, apex slightly in front of the middle, perforated by 

 a large hole, bounded inside by a rounded callus; body large, 

 black, like india-rubber, too big to be contained in the shell when 

 at rest; the reflexed mantle engulfing the shell when active; 

 edge of the mantle smooth; foot fringed; tentacles long; eyes 

 prominent. 



The Great Key-hole Limpet (L. crenulata, Sby.) is easily 

 the giant of the family. It is four to five inches long, with a broad, 

 apical hole, often one inch long. The thick shell is white inside 

 and smooth. The outside shades from pale buff to gray, and 

 is marked by small but distinct radiating ridges, crossed by many 

 concentric lines, grouped in bands showing the stages of growth. 

 The finely scalloped border is the shell's chief beauty. 



Keep describes the mammoth creature that finds this shell 

 inadequate to contain it. It resembles a brick in form and size. 

 The huge foot is yellow, with the black mantle outside. 



Habitat. — Monterey to San Diego, California. 



The Two-spotted Key-hole Limpet (Megatebennus bimac- 

 ulatus, Dall) is a common shell on beaches from Monterey south. 

 It is strongly ribbed from the large apical hole to the margin, and 

 white except for two triangular spots of black on opposite sides. 



In form this little limpet shell resembles that of the giant 

 Lucapina. The animal, however, is much smaller in proportion, 

 though the mantle is able to cover the shell completely. Length, 

 ^ inch. 



Habitat. — California. 



Genus GLYPHIS, Cpr. 



This genus is separated from Fissurella (which its shell 

 resembles externally) by the sudden posterior cutting off square 

 of the callus that bounds the apical hole inside the shell. The 



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