Question

Leucosolenia differs from Scypha in which one of the following characters?

• A. Oscular fringe
• B. Presence of blastula
• C. Intracellular ostia and slow water current
• D. All of the above

Answer 1

The correct option is C Intracellular ostia and slow water current

Leucosolenia has the asconoid type of canal system, which is the simplest. Ostia are present on the surface of the body which is lined by flagellated choanocyte cells.It makes ostia an intracellular. Water enters through ostium into the spongocoel and goes out of the body through the osculum.

In Scypha, the syconoid type of canal system is present. Here, body wall is secondarily folded to form incurrent and radial canals, which open into the spongocoel by an opening called apopyle. Incurrent pores or ostia are found on the outer surface of the body and open into the incurrent canals, which lead into adjacent radial canals through minute openings.
Thus, the correct answer is option C.