He was running wildly towards them, his absurd net dangling behind him.

He gesticulated and almost danced with excitement in front of the lovers.
What the scene meant I could not imagine, but it seemed to me that Stapleton was abusing Sir Henry, who offered explanations, which became more angry as the other refused to accept them.

The lady stood by in haughty silence.

Finally Stapleton turned upon his heel and beckoned in a peremptory way to his sister, who, after an irresolute glance at Sir Henry, walked off by the side of her brother.

The naturalist's angry gestures showed that the lady was included in his displeasure.