Exam 10: Molluscs

Because of "coiling," most gastropods can be characterized as being bilaterally ___________.

Molluscs evolved in fresh water,and therefore the majority of species are found in fresh water.

The cephalopod __________ has a mantle length of 5 to 6 m,eyes up to 25 cm in diameter,and feeds on fish and other squids.

The water current in the body of a cephalopod mollusc provides

The tongue-like,rasping organ in the head of most molluscs is the ______________.

The empty chambers of Nautilus are connected by a cord of living tissue called the __________.

The ______________ is a rod in the stomach of a bivalve which aids in digestion.

Most molluscs are found in fresh water,but a few live in the ocean or on land.

The Monoplacophora

The edible clams,oysters,and scallops belong to the class _____________.

The most primitive conditions in today's molluscs are found in the ____________ with a mantle,calcareous spicules,a radula,and gills.

The largest invertebrate known,the giant squid,belongs to the class _____________.

Classes _______________ and _______________ are small groups of wormlike molluscs with no shell.

The shell of Polyplacophora is divided into (#)_________ valves.

The Solenogasters

Though they evolved from a torted ancestor,opisthobranchs have undergone various degrees of _________________.

The Polyplacophora

The cephalopods are the marine active predators.

With respect to obtaining food,most clams and related organisms can be described as ________.

The group of molluscs which are most endangered are the