93 Beautiful Shells, 



he so perfect and admirable, tliat cigLty pounds 

 was afterwards offered for it, and refused. 



These Naidce havo not a bissus like the Marino 

 Mussels, they are therefore never attached to ono 

 object ; they use their foot as a propeller in tra- 

 versing the muddy floor of tho pond or river, and 

 they have a very funny way of getting along indeed ; 

 first, they open tho valves of the shell, put out tho 

 foot, and, after some littlo hard work, manage to 

 Bet themselves up on edge ; they then proceed by a 

 series of jerks,- leaving a dcepish furrow in the mud 

 behind them. 



We will now go to Fig. 3, the Spined Cytherea, 

 the Cythcrcaj or Venus Diono of naturalists ; the 

 meaning of tho term is the mother of Yenus, who 

 was, as you will remember, the goddess of beauty^ 

 given to this shell, perhaps, because it is entitled to 

 occupy a place at the head of tho CytJicrca, a genus 

 of the CanUidcB, or Cockle family, of which genus 

 there are about seventy-eight living species ; this, 

 as it is tho most rare, is also, perhaps, the most 

 beautiful ; it is found in the seas of America, and is 

 remarkable for the row of spines on the hinder 

 border of each valve ; theso vary much in size and 

 number, being in some individuals long and far 

 apart, in others, short, thick, and closely set. The 



