SHELL S . AQ 



water is warm. The shells range in color from pure white, through 

 all shades of yellow, to bright orange, and some are exquisitely 

 banded and shaded with light and dark brown. The edge of the 

 mantle is fringed with long and short tentacles, among which are 

 thirty silver-blue eyes. As they are not as highly organized as 

 our eyes, Pecten needs a much larger number of them. The scal- 

 lops, unlike most of the mollusks, can swim through the water 



Kazor Shell (^Ensis amerlcana). 



by rapidly opening and shutting the valves. Closing them sud- 

 denly drives out the water in a powerful jet, which by reaction 

 sends the shell forward. It must be a strange and beautiful sight 

 to see a flock of these '' butterflies " flying through the blue water 

 on a fair summer day. Scallops used to be known in Europe as 

 pilgrim shells, because they were used by the pilgrims of the 

 middle ages as a badge. 



A most remarkable family of shellfish are the piddocks, living 

 in England, America, and Borneo. They are all borers. The 

 shells of those which inhabit the English chalk clifl's are snow- 

 white, to match their home. Some bore in rock, some in the red 

 chalk, and the most wonderful of all, the East Indian species, 

 lives in the trunks of dead trees. Their shells are covered with 

 deep grooves crossing each other and forming a sort of rasp. The 

 foot, which is covered with a hard dermal armor, is pressed 

 against the sides and the shell turned about, thus easily scooping 

 out a cavity in the soft chalk. The piddock continually floods his 

 burrow with water to wash out the particles of chalk that collect 

 as he works. The piddock has a little light of its own, so that it 

 could travel safely about after dark were it necessary. This is a 

 peculiarity of many of the creatures of the sea, and often on a 

 summer night in the tropics the water is ablaze with their phos- 

 phorescence. 



Mussels, living in both salt and fresh water, form a large class 

 of mollusks. Some of them can climb about on the rocks by 

 throwing out a byssus thread, pulling themselves up, then fasten- 

 ing another above that, and so on. 



The horse mussel is one of the largest, and very interesting on 

 account of a boarder which it often entertains. A tiny crusta- 

 cean, the pea crab, lives inside its shell in peace and happiness. 

 The crab is not a parasite, as it does not live on the mussel itself, 

 but merely a messmate eating the refuse of its food. 



VOL. L. 6 



