GENERAL HISTOLOGY

Detailed explanation-1: -Sponge larvae (e.g., parenchymula and amphiblastula) are flagellated and able to swim; however, adults are non-motile and spend their life attached to a substratum. Since water is vital to sponges for feeding, excretion, and gas exchange, their body structure facilitates the movement of water through the sponge.

Detailed explanation-2: -Sponge larvae are relatively uniform in their morphology. They are always ciliated, but there can be regions of longer cilia or areas that lack cilia completely. There are two general types of sponge larvae, solid parenchymella larvae and hollow amphiblastula larvae. Sizes range from 50 pm to 5 mm in length.

Detailed explanation-3: -After reproduction, sponge produces larva called as stomoblastula. It has a mouth and feeds on nurse cells within mesogloea and grows for a few days. Stomoblastula develops into an amphiblastula by inverting inside out and brings the flagellated cells on the outer surface, so that the larva can swim in water.

Detailed explanation-4: -Parenchymula is a sponge larva, which appears as a solid ball with exterior flagellated cells. It is a free-swimming larval stage. It is found in some Calcarea and many Demospongiae.

Detailed explanation-5: -Sponges produce free-swimming larval forms not unlike some conceptions of the ancestral animal. These larvae typically live off stored nutrients and settle on the sea floor after a few days.