266 nSSURELLID.^. 



FissuRELLA Gr^ca"^, Linne. 



Patella grcsca, Linn. S. N. p. 1262. F. reticulata, F. & H. ii. p. 469, 

 pi. Ixiii. f. 4, 5, and (animal) pi. B B. f. 7. 



Body cream colour or yellowish, passing into deep orange : 

 mantle ample, extending beyond the sides of the shell, and 

 expanded over the head as a hood or veil ; margin fringed with 

 a row of very small and short but stout cirri, which correspond 

 with the longitudinal ribs of the shell : head tumid and strong : 

 tentacles extensile : eyes black and rather small : gills ybtj 

 thick, brownish: foot yellowish, dilated, with broad sides; 

 the upper part is studded with a row of from 30 to 40 pa- 

 pillae, which are usually by turns larger and smaller. 



Shell forming a cone of variable height, small and appa- 

 rently stunted specimens being more raised than younger ones 

 of a regular growth ; it is solid, opaque, nearly lustreless : 

 sculpture, generally about 25 strong and cord-like, but not 

 much raised, longitudinal ribs, and an equal number of smaller 

 intermediate ones ; all these are crossed by about 30 narrower 

 and imbricated concentric ribs, which by the decussation 

 make the crests of the other ribs nodulous or vaulted ; the 

 surface of living, and especially immature specimens is covered 

 with microscopical longitudinal striae ; in the fry are observ- 

 able a few white dots, arranged in hues as in Puncturella and 

 Emarginula : colour pale yellowish- white with a few broad 

 rays of reddish-, greenish-, or dark-brown,which are sometimes 

 intermingled or variegated : heah very small, oiiLy persistent 

 in the young, inflected and twisted a very little to the left, 

 and forming a spire of between one and two whorls : slit oblong, 

 broader above than below, contracted at the outer sides, which 

 project in the middle like the teeth of a saw : mouth oval, 

 finely scalloped by the ribs and toothed within ; these teeth 

 are often double ; when the shell is placed on its base, the 

 outline of the mouth is more or less arched on each side, and 

 resembles the sole of a human foot: inside porcellanous, ex- 

 hibiting the coloiu'ed rays in young specimens ; it is dehcately 

 lineated around the margin, as in the interior of all shells 

 belonging to other genera of the same family: j^allial scar 

 wide and irregular, having a large central impression analogous 

 io that oi Patella. L. 1-25. B. 0-75. 



* Inhabiting the Archipelago. 



