Final answer:
The class referred to as “Scaphopoda” in Phylum Mollusca is known for organisms like tusk shells, which have a single conical shell open at both ends, and a specialized radula for feeding, without ctenidia for respiration.
Step-by-step explanation:
Class Scaphopoda in Phylum Mollusca
The class within Phylum Mollusca that is referred to as “Scaphopoda” comprises organisms colloquially known as tusk shells or tooth shells. Members of the Scaphopoda class, such as the genus Dentalium, possess a single conical shell that is open at both ends. These animals typically bury themselves in sand with the anterior opening of the shell exposed to water, allowing them to catch prey with their ciliated tentacles. The head of scaphopods is not well developed, but they are equipped with a radula for feeding. Unlike other mollusks, scaphopods do not have ctenidia; instead, they respire through a mantle cavity that forms a tube open at both ends.
Within the diversity of mollusks, Scaphopoda stands out for having a unique body form adapted to their burrowing lifestyle. Despite their differences, mollusks share some common structural traits, such as a muscular foot, usually used for locomotion, a visceral mass containing most internal organs, and a mantle that may secrete a protective shell.