The squid that “attacked” the reverend and his companion in their dory was on the smaller end of how large adult giant squids (Architeuthis dux) can be, but was still massive. The mantle (body) of the squid is largely removed in this photograph; only the beak and tentacles remain.
In the late 1800s, an unusually large number of giant squid strandings occurred in Newfoundland and New Zealand. This may have been due to a change in the abyssal waters in those areas, or an increased population simply showing up more often, since sperm whales (their primary predators) were nearly hunted to extinction.
After this “attack” (more likely the flailing tentacles of a dying squid happening to hook onto a boat), Rev. Harvey, already keenly studying the natural history of St. John’s, Newfoundland, found ways to discern some of the habits and behaviors of giant squid, despite not being able to directly observe live specimens. It was through his published accounts that many naturalists in Britain and North America became acquainted with one of the giants of the deep sea.