32 



problematical about the relationship, which further researches are needed 

 to elucidate. 



Patellacea. Chitonacea. 



Family 1. PATELLACEA. 



Shell; dish-shaped, of one more or less depressly conoid piece ; 

 margin entire. 



In addition to the genus of true Limpets, Patella, we include in this 

 family a group of which Mr. Cuming possesses an interesting series of 

 species, but of which few are as yet described, Scntella. The shells have 

 rather the appearance of Emarginulce without the slit. 



Patella. Scutella. 



Genus 1. PATELLA, Linnceus. 



Animal ; with two subulate tentacles, bearing eyes on the outer 

 sides of their sivollen bases; mantle-margin fringed ; bra?ichial 

 plume forming a fixed cordon of minute close-set plates, placed 

 betioeen the mantle and base of foot, and ranging nearly round 

 the body ; foot a large ovate or round disc, with plain sides. 

 (Forbes.) 



Shell ; ovate or rounded, more or less convex, dish-shaped, not 

 spiral ; apex sometimes central, generally more or less inclined 

 anteriorly, mostly radiately ribbed or ridged, sometimes scaled, 

 generally crenulated at the margin. 



The Patella are so named from a resemblance in the form of their shell 

 to the patella, or dish, formerly used by the Latins for carrying meat in 

 their sacrifices. In structure it is the most simple of shells, being a plain, 

 un convoluted shield, without perforation or notch, more or less raised in 

 convexity, inclining to an apex, rarely more than superficially developed, 

 sometimes bent anteriorly into an incurved hook. From this apex, radiate 

 ridges or ribs which are sometimes scaled, and have the interstices not un- 

 frequently wrought into lattice-work by concentric ridges. The radiating 

 sculpture is, however, mostly smooth, though presenting most diversified 

 patterns in detail. The painting of the Patella is also much varied ; rays 

 of different colour mostly predominate, and they are so modified by exter- 

 nal causes in different individuals of the same species, that many have been 

 described several times over. 



