304 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



up another zone which is ordinarily only washed by the waves and spray, 

 but is in part occasionally covered by unusually high tides. As the 

 tides do not rise very high in this region these zones are all much nar- 

 rower and less distinctly marked than on the coast further north, and 

 especially on the coast of Maine and in the Bay of Fundy, but yet they 

 can always be easily recognized and distinguished by their peculiar forms 

 of animal and vegetable life. Pools of sea-w^ater left by the tide fre- 

 quently occur in each of these zones, among the rocks, and afford 

 excellent opportunities for studying and collecting the animals. 



The animals of rocky shores are to be sought for in a variety of ways. 

 A few occur quite exposed, clinging to the rocks or weeds, in defiance of 

 the surf. These are chiefly univalve shells, barnacles, and such animals 

 as grow like plants, firmly attached to solid objects, among these are 

 the bryozoa, hydroids, and sponges. A much larger number seek shel- 

 ter under the rocks, or on their lower sides, or in crevices and cavities 

 between them 5 these must be sought by turning over the rocks and ex- 

 ploring the crevices concealed by the Fuciis, &c. Many other species 

 conceal themselves still more effectually by burrowing in the mud, 

 gravel, and sand beneath and between the rocks ; these are often 

 uncovered in turning over the rocks, but must also be sought for 

 by digging with a spade, stout trowel, or some other tool, in the 

 dirt exposed when the rocks are removed. The number of curious 

 species of annelids, holothurians, bivalve- shells, actiniae, &c., which 

 can be unearthed in this way is always very surprising to the inexpe- 

 rienced in this kind of collecting. Still other kinds can be found by 

 carefully examining the pools and discovering the smaller animals by 

 their motions, or by the shadows that they cast when the sun shines, 

 or by noticing their burrows, or, if time will not admit of a more care- 

 ful examination, by sweeping a fine hand-net through the weeds along 

 the edges. Many small Crustacea, shells, etc., may also be found cling- 

 ing to the corallines and other algse growing in such pools, or even 

 among the alg?e lying upon the rocks, and especially among masses of 

 detached algae, thrown up by the waves. 



In the uppermost zone the animals are of comparatively few kinds^ 

 but these usually occur in great abundance. The most conspicuous is, 

 perhaps, the common " rock-barnacle^' or ^' acorn-shell," Balanus hal- 

 anoides, which adheres firmly to the rocks by its base and can resist 

 the most violent surf, even on the outer ocean shores. When left by 

 the tide these dull white conical shells are not calculated to attract 

 much attention, except on account of their vast numbers, for they 

 sometimes completely whiten the rocks for long distances along the 

 zone in which they flourish best, and even so crowd against each other 

 that they cannot assume their normal form, but become greatly elon- 

 gated. But when the tide comes in, each one lifts up the double-door 

 which closes the aperture at the summit of the shell and puts out an 

 organ, bearing a cluster of gracefully curved and fringed arms, which 



