τὸ πλῆθος οὐκ εὐαρίθμητον ἦν → the crowd wasn't easy to count, the crowd was not small, it was not a small crowd
v. κατερείπω.
κατήρῐπον: эп. aor. 2 к κατερείπω.
κατήριπον them. aor. act. van κατερείπω.