Today, surume basically means dried squid but there is an opinion that it is a corrupted pronunciation of 'sumimure,' which once was a generic term for schools of ink-spurting creatures and dried octopus used to be referred to as surume as well.
スルメといえば現在では基本的にイカの乾燥させたものを指すが、墨を吐く群を「墨群（すみむれ）」と呼んでいたところから転訛したという説があり、かつては乾燥させたタコもスルメと呼ばれていた｡