[Illustration: FIG. 4.--BALANUS SHELLS] A more lovely sight than the typical rock pool of the West coast one can hardly imagine. Around lies the rugged but sea-worn rock, partly hidden by dense patches of the conical shells of the _Balanus_, with here and there a snug cluster of young mussels held together by their intertwining silken byssi. The surface is further relieved by the clinging limpet, the beautifully banded shells of the variable dog-periwinkle, the pretty top shells, and a variety of other common but interesting molluscs. Clusters of the common bladdery weeds are also suspended from the dry rock, and hang gracefully into the still water below, where the mantled cowry may be seen slowly gliding over the olive fronds. Submerged in the peaceful pool are beautiful tufts of white and pink corallines, among which a number of small and slender starfishes may climb unnoticed by the casual observer; while the scene is brightened by the numerous patches of slender green and red algæ, the thread-like fronds of which are occasionally disturbed as the lively little blenny darts among them to evade the intruder’s glance. Dotted here and there are the beautiful anemones--the variously-hued animal flowers of the sea, with expanded tentacles gently and gracefully swaying, ready to grasp and paralyse any small living being that may wander within their reach. Here, under a projecting ledge of the rock, partly hidden by pale green threads, are the glaring eyes of the voracious bullhead, eager to pounce on almost any moving object; while above it the five-fingered starfish slowly climbs among the dangling weeds by means of its innumerable suckers. In yonder shady corner, where the overhanging rock cuts off all direct rays of the sun from the deeper water of the pool, are the pink and yellow incrustations of little sponges, some of the latter colour resembling a group of miniature inverted volcanic cones, while on the sandy floor of the pool itself may be seen the transparent phantom-like prawn, with its rapidly moving spinnerets and gently-waving antennæ, suddenly darting backward when disturbed by the incautious approach of the observer; and the spotted sand-crab, entirely buried with the exception of its upper surface, and so closely imitating its surroundings as to be quite invisible except on the closest inspection. Finally, the scene is greatly enlivened by the active movements of the hermit-crab, that appropriates to its own use the shell which once covered the body of a mollusc, and by the erratic excursions of its cousin crabs as they climb over the weedy banks of the pool in search of food. [Illustration: FIG. 5.--A CLUSTER OF MUSSELS]