Schooling together has also given the bonitos their name of amia Similarly, Athenaeus (vii. 278 a; Cf. 324 d) quotes Aristotle as defining amia as not solitary, i.e. running in schools. Actually the term is probably foreign, perhaps of Egyptian origin (Cf. Thompson, , p. 13). and I think this is true of year-old tunnies as well.Plutarch takes pelamys to be compound of pelein to be and hama with, with references to their running in schools. It was also anciently presumed to be a compound of pelos mud and myein be shut in or enclosed, because of its habit of hiding in the mud (Cf. Aristotle, 599 b 18; Pliny, ix. 47). Most scholars now regard it as a loan from the Mediterranean substratum, although Thompson (, p. 198) suggests that it may be of Asiatic origin, since it was used especially of the tunny in the Black Sea. As for the other kinds which are observed to live in shoals in mutual society, it is impossible to state their number. Let us rather, therefore, proceed to examine those that have a special partnership, that is, symbiosis. One of these is the pinna-guard,See Thompson, , p. 202. over which ChrysippusVon Arnim, ii, p. 208, frag. 729 b (Athenaeus, 89 d). Cf. also fragments 729, 729 a, and 730. On the place of the pinna in Chrysippus’ theology see A. S. Pease, xxxiv (1941), p. 177. spilled a very great deal of ink; indeed it has a reserved seat in every single book of his, whether ethical or physical.Cf. . 1035 b, 1038 b. Chrysippus has obviously not investigated the sponge-guardA little crab that lives in the hollow chambers of a sponge. See Thompson, loc. cit. ; otherwise he could hardly have left it out. Now the pinna-guard is a crab-like creature, so they say, who lives with the pinnaOn this bivalve shellfish see Thompson, , p. 200; Mair on Oppian, ii. 186. and sits in front of the shell guarding the entrance. It allows the pinna to remain wide open and agape until one of the little fish that are their prey gets within; then the guard nips the flesh of the pinna and slips inside; the shell is closed and together they feast on the imprisoned prey.

The sponge is governed by a little creature not resembling a crab, but much like a spider.Nevertheless, it is a crab, Typton spongicola. Now the spongeCf. Aelian, viii. 16; Aristotle, v. 16 (548 a 28 ff.); Pliny, ix. 148; Antigonus, 83; Mair on Oppian, v. 656; Thompson, , pp. 249-250. is no lifeless, insensitive, bloodless thing; though it clings to the rocks,Cf. W. Jaeger, , p. 116, n. 1. as many other animals do, it has a peculiar movement outward and inward which needs, as it were, admonition and supervision. In any case it is loose in texture and its pores are relaxed because of its sloth and dullness; but when anything edible enters, the guard gives the signal, and it closes up and consumes the prey. Even more, if a man approaches or touches it, informed by the scratching of the guard, it shudders, as it were, and so closes itself up by stiffening and contracting that it is not an easy, but a very difficult, matter for the hunters to undercut it.

The purplefishSee Aristotle, v. 15 (546 b 19 ff.) quoted in Athenaeus, 88 d - 89 a; iii. 11 (761 b 32 ff.); Thompson, , pp. 209-218. lives in colonies which build up a comb together, like bees. In this the species is said to propagate; they catch at edible bits of oystergreen and seaweed that stick to shells, and furnish each other with a sort of periodic rotating banquet, as they feed one after another in series.