“Cyanea!” I cried. “Cyanea! Behold the Lion’s Mane!” The strange object at which I pointed did indeed look like a tangled mass torn from the mane of a lion. It lay upon a rocky shelf some three feet under the water, a curious waving, vibrating, hairy creature with streaks of silver among its yellow tresses. It pulsated with a slow, heavy dilation and contraction. “It has done mischief enough. Its day is over!” I cried. “Help me, Stackhurst! Let us end the murderer forever.” There was a big boulder just above the ledge, and we pushed it until it fell with a tremendous splash into the water. When the ripples had cleared we saw that it had settled upon the ledge below. One flapping edge of yellow membrane showed that our victim was beneath it. A thick oily scum oozed out from below the sto