Chapter III.

1. When animals are divided in three ways into aquatic and land animals, because they either breathe air or water, or from the composition of their bodies; or, in the third place, from their food, their manner of life will be found to agree with these divisions. For some follow both the composition of their bodies and the nature of their food, and their respiration of either water or air. Others only agree with their composition and food.

2. The testacea which are immoveable live by a fluid which percolates through the dense parts of the sea, and being digested because it is lighter than the sea water, thus returns to its original nature. That this fluid exists in the sea, and is capable of infiltration is manifest, and may be proved by experiment; for if anyone will make a thin waxen vessel, and sink it empty in the sea, in a night and a day, it may be taken up full of water, which is drinkable.

3. The acalephe (actinia) feeds upon any small fish which may fall in its way. Its mouth is placed in the centre of its body. This organ is conspicuous in the larger individuals: like the oyster, it has a passage for the exclusion of its food, which is placed above. The acalephe appears to resemble the internal part of the oyster, and it makes use of the rock, as the oyster does of its shell. (The patella also is free, and wanders about in search of food.)

4. Among the locomotive testacea, some are carnivorous, and live on small fish, as the purpura, for this creature is carnivorous, it is therefore caught with a bait of flesh: others live upon marine plants. The marine turtles live upon shell-fish, for which purpose they have a very powerful mouth; for if any of them take a stone or anything else, they break and eat it. This animal leaves the water and eats grass. They often suffer and perish, when they are dried up as they float on the surface, for they are not able to dive readily.

5. The malacostraca are of the same nature, for they eat everything; they feed upon stones and mud, seaweeds and dung, as the rock crabs, and are also carnivorous. The spiny lobsters also overcome large fishes, and a kind of retribution awaits them in turn, for the polypus prevails over the lobster, for they are not inconvenienced by the shell of the lobster, so that if the lobsters perceive them in the same net with them, they die from fear. The spiny lobsters overcome the congers, for their roughness prevents them from falling off. The congers devour the polypi which cannot adhere to them on account of the smoothness of their surface; all the malacia are carnivorous.

6. The spiny lobsters also live on small fish, which they hunt for in their holes, for they are produced in such parts of the sea as are rough and stony, and in those places make their habitations; whatever they capture, they bring to their mouth with their double claw, as the crabs do. When not frightened they naturally walk forwards, hanging their horns down at their sides. When alarmed they retreat backwards, and extend their horns to a great distance. They fight with each other like rams with their horns, raising them and striking each other. They are often seen in numbers as if they were gregarious.

7. The malacostraca lead this kind of life. Among the malacia the teuthis and sepia prevail over the large fish. The polypus generally collects shells which it empties of their contents and feeds upon them, so that those who seek for them find their holes by the shells that are scattered about. The report that they eat each other is a mistake; but some have the tentacula eaten off by the congers.