Question: What is the  large marine bivalve mollusc species with the scientific name "Panopea generosa"?
Sentence (from "Tresus capax"): The two species commonly known as horse clams inhabit the Pacific coast intertidal zones: the pacific gaper, "T. nuttallii", more abundant south to California; and the fat gaper, "T. capax", more abundant north to Alaska.
Relevant evidence: No