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. CHAPTER IV. 1. All fish at the season of oviposition live upon ova; in the rest of their food they are not all so well agreed, for some of them are only carnivorous, as the selachos, conger, channa, thynnus, labrax, sinodon, amia, orphus, and muræna; the trigla lives upon fuci, shell-fish, and mud; it is also carnivorous. The cephalus lives on mud, the dascillus on mud and dung. The scarus and melanurus on sea-weed, the salpa on dung and fuci, it will also eat the plant called horehound; it is the only fish that can be caught with the gourd.