54 



CLASS MOLLUSCA. 



and a half in length, and is found in the European seas 

 Lamarck mentions as many as eleven species. 



Bulla lignaria. 



The Nail-Shaped Crepidula, 

 {Crepidula iingiiiformis.) 



The genus Crepidula takes its name from its bearing 

 some resemblance to a little shoe; none of the species 

 are found in Europe. Of these there are about six, but 

 they are all confined to the seas of warm climates. 



The Mediterranean Umbrella, 

 ( Umbrella Mediterranca.) 

 The Umbrella Mediterranea, as its name implies, is 

 found in the Mediterranean, and in the Gulf of Tarento. 

 The shell of the Umbrella is singular, from the lower 

 part of its circiunference being surrounded by a border 

 of a substance much softer than the shell itself. 



The Clouded Fissurella, (Fissurella nimbosa.) 



The lissurella jiimbosa is found in various and distant 

 parts of the world, — in the north of Europe, the western 



