148 MARINE ANIMALS OF MASSACHUSETTS BAY. 



bound by any law to keep within a certain distance of the shore ? 

 These questions would seem to be easily answered, for wherever 

 we go on the surface of the sea, and as far as the eye can pene- 

 trate into its depths, we find it full of life ; tod yet a closer ex- 

 amination shows that all these beings have their appointed boun- 

 daries. Along the shores, animal and vegetable life seems to be 

 distributed in certain definite combinations. Those who are 

 familiar with rocky beaches readily recognize the different bands 

 of color produced by the various kinds of sea-weed growing at 

 given distances between high and low-water-mark. First comes 

 the olive green rockweed (the Pucus), and with it are found bar- 

 nacles and small Crustacea, myriads of which are to be seen hop- 

 ping about in this rockweed when the tide is out. Below these 

 are the brown crispy Rhodersperms and Melanosperms, and asso- 

 ciated with them are Star-fishes, Crabs, and Cockles. Next in 

 order is the Laminarian zone. Here we have the broad fronds 

 of the Laminaria, the " devil's aprons," as the fishermen call 

 them ; in this zone is the home of the Sea-urchin, and here wiU 

 be found also a few small fishes. Lastly we have the Coralline 

 zone, so called on account of the lime deposit in the searweeds, 

 giving them the rigidity of corals ; among these the Lobsters 

 make their appearance, and here are to be found also numerous 

 clusters of Hydroids, the nurses of the Jelly-fishes. 



This distribution is not casual ; these belts of animal and vege- 

 table life are sharply defined and so constantly associated, that 

 they must be controlled by the same physical laws. The first 

 important investigations on this subject were made by Orsted, 

 the distinguished Danish naturalist. He undertook a complete 

 topographical survey of the coast near which he lived, carrying 

 his soundings to a depth of some twelve fathoms, and found that 

 both the fauna and flora of the shore were divided, according to 

 the depth of the water, into bands of vegetable and animal life, 

 corresponding very nearly with those given above. His observa- 

 tions were, however, limited, not extending beyond the neighbor- 

 hood of his home. It is to Edward Forbes, the great English 

 naturalist, whose short life was so rich in results for science, that 

 we owe a more complete and extensive investigation of the whole 

 subject. 



