Shrimps and prawns of many shapes and colours inhabit every pool. One small species, abundant on the algae, combines the colour changes of a chameleon with the form and manner of travel of a measuring-worm, looping along the fronds of seaweed or swimming with the same motion. Another variety of shrimp resembles the common wood-louse found under pieces of bark, but is most beautifully iridescent, glowing like an opal at the bottom of the pool. The curious little sea-spiders keep me guessing for a long time where their internal organs can be, as they consist of legs with merely enough body to connect these firmly together. The fact that the thread-like stomach and other organs send a branch into each of the eight legs explains the mystery and shows how far economy of space may go. Their skeleton-forms, having the appearance of eight straggling filaments of seaweed, are thus, doubtless, a great protection to these creatures from their many enemies. Other hobgoblin forms with huge probosces crawl slowly over the floors of the anemone caves, or crouch as the shadow of my hand or net falls upon them. The larger gorgeously coloured and graceful sea-worms contribute not a small share to the beauty of Fundy tide-pools, swimming in iridescent waves through the water or waving their Medusa-head of crimson tentacles at the bottom among the sea-lettuce. These worms form tubes of mud for themselves, and the rows of hooks on each side of the body enable them to climb up and down in their dismal homes. Much of the seaweed from deeper bottoms seems to be covered with a dense fur, which under a hand lens resolves into beautiful hydroids,--near relatives of the anemones and corals. Scientists have happily given these most euphonious names--_Campanularia_, _Obelia_, and _Plumularia_. Among the branches of certain of these, numbers of round discs or spheres are visible. These are young medusae or jelly-fish, which grow like bunches of currants, and later will break off and swim around at pleasure in the water. Occasionally one is fortunate enough to discover these small jellies in a pool where they can be photographed as they pulsate back and forth. When these attain their full size they lay eggs which sink to the bottom and grow up into the plant-like hydroids. So each generation of these interesting creatures is entirely unlike that which immediately precedes or follows it. In other words, a hydroid is exactly like its grandmother and granddaughter, but as different from its parents and children in appearance as a plant is from an animal. Even in a fairy-story book this would be wonderful, but here it is taking place under our very eyes, as are scores of other transformations and "miracles in miniature" in this marvellous underworld.