CHAPTER LIII: THE WIDE-MOUTHED SHELLS 



Family Stomatellid^ 



Shell small, pearly within, flattened, limpet-like or ear- 

 shaped and spiral, but without holes or slit. 



This family lives in tropical regions of the Pacific Ocean. 

 Classification is likely to need revision as the living mollusks 

 are studied. Few have ever been seen. 



Within this family a series of genera show the gradations 

 between the coiled top shell forms, with narrow mouths, closed 

 by an operculum, through widening ear shell forms to the limpet 

 form in which the spiral disappears. The bearing of this chain 

 of evidence upon the problems of evolution among mollusks is 

 obviously important. 



Stomatella has a depressed spire, few whorls, a regular top 

 shape and an operculum. Stomatia has a short spire and no 

 operculum. The animal is too large for the shell. Gena is ear- 

 shaped like Haliotis. Broderipia illustrates the limpet form of 

 shell in this family. The shell has an apical hook at the posterior 

 end. It is shaped like a sugar scoop. 



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