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CHAPTER X
Scallops, Oysters and
Other Clams
Class PELECYPODA
The bivalves or clams are dwellers of fresh, marine or brackish waters.
They lack a head and are without jaws or radular teeth; they are protected
by a pair of shelly valves which are connected or hinged by a horny ligament
and which are moved by the contraction of one to three muscles attached
to the inner sides of the valves; feeding is usually done with the aid of their
ciliated or hair-covered gills. Further details have been presented in the
chapter on "The Life of the Clam." The class is also known as Lmnelli-
branchia, Bivalvia or Acephala. The class may be divided into the follov/ing
orders and suborders:
Order PALAEOCONCHA
Suborder SOLEMYACEA (Awning Clams)
Order PROTOBRANCHIA »
Suborder NUCULACEA (Nut Clams)
Order FILIBRANCHIA
Suborder TAXODONTA (Ark Shells)
Suborder ANISOMYARIA (Scallops, Oysters, Sea Mussels)
Order EULAMELLIBRANCHIA
Suborder SCHIZODONTA (River Mussels)
Suborder HETERODONTA (Cockles, Lucines, Venus)
Suborder ADAPEDONTA (iVlya and Razor Clams, Teredos)
Suborder ANOMALODESMACEA (Pandora Clams)
Order SEPTIBRANCHIA
Suborder POROMYACEA (Dipper Clams, Meat Eaters)
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