Where is a metaphor?
The metaphor is contained in the last sentence, “He was in a picture with a frame of water, and his operations, clearly, must take place within that frame.” A metaphor is a comparison of two unlike things…Rainsford was trapped on Shiptrap Island with General Zaroff hunting him like one of the animals he used to hunt himself. The island and all it contained was framed by the sea much the same as a picture might be surrounded by a frame.