The crystal that separated the water from the atmosphere had the density of millions of leagues,--an insuperable obstacle interposed between two worlds that do not know each other.
The sailor recalled the imperfect vision of the ocean inhabitants.

In spite of their bulging and movable eyes that enable them to see before and behind them, their visual power extends but a short distance.

The splendors with which Nature clothes the butterfly cannot be appreciated by them.

Absolutely color-blind, they can appreciate only the difference between light and darkness.
Complete silence accompanies their incomplete vision.

All the aquatic animals are deaf, or rather they completely lack the organs of hearing, because they are unnecessary to them.