Some are known to the fishermen of the Indian ocean, others to the toilers of the Egyptian gulf, others to the islanders, others to the men of Mauretania. Μαυρούσιοι.  cf. Strabo, ii. 33.  Great and small were all alike created by this first command, by this ineffable power.  What a difference in their food!  What a variety in the manner in which each species reproduces itself!  Most fish do not hatch eggs like birds; they do not build nests; they do not feed their young with toil; it is the water which receives and vivifies the egg dropped into it.  With them the reproduction of each species is invariable, and natures are not mixed.  There are none of those unions which, on the earth, produce mules and certain birds contrary to the nature of their species.  With fish there is no variety which, like the ox and the sheep, is armed with a half-equipment of teeth, none which ruminates except, according to certain writers, the scar. e.g. Arist., De Anim. viii. 2 and Ælian, ii. 54.  All have serried and very sharp teeth, for fear their food should escape them if they masticate it for too long a time.  In fact, if it were not crushed and swallowed as soon as divided, it would be carried away by the water.