gre ed. Burnet 1903 263bΞένος
ὡς εἶδος μὲν ὅταν ᾖ του, καὶ μέρος αὐτὸ ἀναγκαῖον εἶναι τοῦ πράγματος ὅτουπερ ἂν εἶδος λέγηται: μέρος δὲ εἶδος οὐδεμία ἀνάγκη. ταύτῃ με ἢ 'κείνῃ μᾶλλον, ὦ Σώκρατες, ἀεὶ φάθι λέγειν.
eng tr. Jowett 1817-1893STRANGER:
That a class is necessarily a part, but there is no similar necessity that a part should be a class; that is the view which I should always wish you to attribute to me, Socrates.
http://www2.hf.uio.no/common/apps/permlink/permlink.php?app=polyglotta&context=record&uid=290200a7-cfdd-11e7-8793-0050569f23b2