1) Found that there's a hiragana mistake in verb of 泳ぐ, the volitional form is same as the imperative 泳げ. As following,
2) And two very minor problems of the consistency, also in the conjugation chart.
When click into the entries of "乗る・のる" and "遊ぶ・あそぶ", shown "のる・のる" and "あそぶ・あそぶ" respectively on the heading. (Check with others, the heading show correctly)