Then a rather light blow on the jaw, just under Pen's right ear again.

The larger midshipman was now thoroughly alarmed.

He feared that Darrin could do whatever he willed, and shivered with wonder as to when the knockout blow would come.
The truth was, Pennington was still putting up a better battle than he himself realized, and Darrin was not disposed to take any foolish chances through rushing the affair.

Thus, the third round ended.
By the time that they came up for the fourth round, after both men had undergone some vigorous handling by their respective seconds, Pennington was a good deal revived and far more confident.
Dave's tactics were the same in the fourth round.

Pennington didn't find time to develop much in the way of tactics for himself, save to defend himself.
During the first minute no important blows were landed on either side.
Then, suddenly, Dave darted in and under, and brought a right-arm hook against Pen's nose in a way that started that member to bleeding again, and with a steady flow.
That jarred the larger midshipman.