The Key-hole Limpets 



almost uniform in size and daintily beaded. The slit is deeper 

 than in most species, a clear identification. Colour, pale flesh 

 tint or green, with white rays. Length, f inch. 

 Habitat. — Florida, West Indies. 



SHIELD SHELLS 

 Genus SCUTUS, Montf. 



Shell oblong, depressed to platter form, thick, squarish at 

 ends, with obscure notch in front margin; apex obscure near 

 posterior end, pointed backward; surface without radiating 

 ribs or markings; body black or blotched with black; mantle 

 enveloping the shell ; snout and tentacles long. 



S. anatinus, Donovan, is three inches long, its shell buflF 

 in colour, with white lining, marked with orange or reddish 

 stains. It is an Australian mollusk and interesting as a type 

 of the most primitive genus in its family. It has no key-hole 

 nor slit nor groove; these characters have been progressively 

 acquired by the family in course of its evolution. 



The Giant Shield Shell (S. gigas. Martens) is pale yel- 

 low, with strong concentric waving lines and projecting edges 

 on its thick shell. It is nearly four inches long, and three inches 

 wide. Under the name of saru-awahi it is taken from the waters 

 of Northern Japan and used by the natives as a staple sea food 

 the year round. 



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