τὸ πλῆθος οὐκ εὐαρίθμητον ἦν → the crowd wasn't easy to count, the crowd was not small, it was not a small crowd
myrīcē: ēs, or myrīca, ae, f., = μυρίκη,
I the tamarisk, a kind of shrub, Plin. 13, 21, 37, § 116; 24, 9, 41, § 67.—Prov., to signify something impossible: pinguia corticibus sudent electra myricae, Verg. E. 8, 54.