Certain that there is no int., pelagic larval form.
Dr Natterer, the chemist of the " Pola " expeditions, has expressed the opinion that the poverty of the pelagic fauna is solely due to the want of circulation in the depths.
- A great part of the bottom of the Mediterranean is covered with blue muds, frequently with a yellow upper layer containing a considerable proportion of carbonate of lime, chiefly shells of pelagic Foraminifera.
In the shallower tropical waters, especially on the central ridge, considerable areas are covered by Pteropod ooze, a deposit consisting largely of the shells of pelagic molluscs.
Pelagic organisms, floating on the surface of the open sea, propelling themselves feebly by the pumping movements of the umbrella produced by contraction of the sub-umbral musculature, and capturing their prey with their tentacles.