52 Beautiful Shells. 



comes from the Greek Ptero, pronounced tero, 

 meaning a wing, and cerus — waxen. Both the 

 generic and specific names of the second refer to 

 the peculiar conformation of the shell, being derived 

 from the Latin, and meaning a straight line or 

 beak. 



On Plate III. will be found the Imbricated Pur- 

 pura (P. imbrieata), Fig. 1, which claims a close 

 alliance with the Whelks. The generic name has 

 reference to the dye yielded by this, as well as all 

 the shells of the genus; the specific name comes from 

 the Latin imbrex — the gutter-tile ; thus imbricated, a 

 term often used in Natural History, means ridged, 

 like the roof of a house, where the tiles are placed 

 to overlap each other, so that the rain will run off. 

 The Persian Purpura, or, as it is called in Latin, 

 Purpura Persica y Pig. 2, is another handsome shell 

 of this family group ; its name indicates the place 

 where it is found. The other species described 

 comes from South America, and the P. lajoillus 

 (the meaning of the specific name has already been 

 explained), is common on our shores, being found 

 in great abundance on the rocks at low water. 

 We read' in Scripture of Tyrian purple, and there 

 is every reason to suppose that the rich colour was 

 obtained from these and other shell-fish. 



