William Adam was a Dutch–Belgian malacologist who specialised in cephalopods. Adam described a number of cuttlefish and bobtail squid species, including Euprymna hoylei, Sepia cottoni, Sepia dollfusi, Sepia dubia, Sepia reesi, Sepia sewelli, Sepia thurstoni, Sepia vercoi, and Sepiola knudseni.