COLLECTING 9 



them the curious little sea-spiders (Pycnogotiidce), animals which 

 seem to be all legs. 



Mollusks, and other classes as well, differ in different latitudes. 

 On the rocks of the Northern shores Littorina and Purpura shells 

 are very abundant, the latter in various colors and beautifully 

 striped. Limpets are also plentiful, but are not as conspicuous, 

 since they have flat, disk-shaped shells. When their capture is 

 attempted, they must be taken unawares and pushed quickly 

 aside, else they take such a firm hold of the rock that it is diffi- 

 cult to dislodge them. Near low-water mark under ledges will 

 perhaps be found chitons, which are easily recognized by their 

 oval, jointed shells. On the California coast in like localities 

 will be found the beautiful Haliotis, Acmcea, and chitons. Every 

 stone that is lifted will disclose numbers of little amphipods 

 (Gammarus), which will scuttle away on their sides to other 

 shelter; worms will suddenly disappear into the mud, and per- 

 haps a crab, here and there, having no alternative, will make a 

 stand and fight for his liberty. Flat against the stone and not 

 easily perceived may be a chiton, a planarian worm, or a uudi- 

 branch. And just below the water's edge are sea-urchins and 

 starfishes, which grow in numbers as the eye becomes accustomed 

 to the search. 



The rock pools are natural aquaria, more interesting by far 

 than any prepared by man. The possibilities of these little sea- 

 gardens are beyond enumeration. The longer one studies them 

 the more one finds. In them all classes of seaweeds and marine 

 invertebrates may be found and their habits watched. The great 

 beauty of these pools gives them an esthetic charm apart from 

 the scientific interest they excite. Perhaps one may find here a 

 sponge, and removing it to a shallow vessel of sea-water can 

 watch the currents of water it creates. Several sponges of the 

 same species placed in contact will at the end of two days be 

 closely united. If the sponges are of different species they will 

 not coalesce. 



In the clefts and crannies of the rocks are various fine sea- 

 weeds, often of the red varieties, sea-anemones, hydroids, poly- 

 j crustaceans, mollusks, and ascidians. Crabs will be snugly 



