2472 The Sea-side Book. 



the sub-tribe of heart urchins (Spatangacece), very numerous species, many of them of 

 highly curious and elegant forms, exist in the oolite and the chalk, and abound in 

 many tertiary deposits. They all characterise marine strata, and generally indicate 

 shallow parts of the sea. Very few of the kinds now living have. been found fossil- 

 ized, except in deposits which are evidently of a recent date. Thus in these, as in 

 other races of animals, there have been successions of species, each marking its 

 own era. 



" Among the common productions of sandy shores several species of zoophytes 

 present themselves, generally in a dead state, the fleshy parts having wholly disap- 

 peared, leaving merely the skeleton or skin behind. These skeletons often resemble 

 sea-weeds, both in the plant-like forms they assume, and in bearing along the branches 

 little membranous sacs, which look like minute flowers or seed-vessels, and are, indeed, 

 organs of a similar nature, being the ovaries in which the germs of the young polypes 

 are contained. From sea-weeds the skeletons in question may always be known by 

 their horny or bony texture, and their generally pale, testaceous colour. There is but 

 one group of sea-plants, the jointed corallines, which so far resemble some of them in 

 being hard, and indeed stony in substance, as to lead to their being commonly con- 

 founded, even by naturalists, with skeletons of zoophytes. But these are rock plants, 

 which we shall speak of in another chapter. Most of the zoophytes, also, are natives 

 of rocky places, or of shingly ground, such as oyster-beds, beyond the reach of the 

 tide. And it is only the species which are accidentally thrown up by the waves which 

 we meet with on strands. Of these, one of the most common is Flustra foliacea, * * 

 a much-branched species, of a papery substance and dirty-white colour, flat, and built 

 up of innumerable little oblong cells, placed back to back, like those of a honey-comb, 

 and each crowned (as may readily be seen with the help of a pocket-lens) by four stout 

 spines. It is these spines which give the surface of the poh/pidom (as the plant-like 

 body is called) its peculiar, rough or harsh feel, observable if the finger be passed over 

 the surface from the apex toward the base. 



" This structure of cells {polypidom or leafy-body) is not the remains of a single 

 animal, but of a community of individuals as numerous as those of one of our cities, 

 each of which dwelt within the narrow compass of one of the cells, in which he was 

 born, lived and died. This cell was his house, more literally his skin, within which 

 he enjoyed an independent existence, at the same time that he was linked, by a com- 

 mon circulation, to the cells above and below him ; and thus had a double existence, 

 being at the same time himself and a part of 'the neighbours ;' or rather, a part of 

 a compound animal represented by the polypidom itself, and whose individuality is 

 exhibited by the regularity of its growth ; just as a plant, which may be considered as 

 a community of separate leaves, proves its individuality by the orderly manner in 

 which those leaves are arranged. The life enjoyed by this common Flustra may be 

 taken as an example of that of a class of animals to which it is related, the compound 

 polypes whose remains, recent and fossil, constitute an enormous portion of the fossil- 

 ized crust of the earth. The general form and structure of the individual polypes 

 may be illustrated by the largest members of the group, the sea Anemones, whose 

 flower-like bodies are seen expanded in every rock-pool left by the tide. The little 

 polypes which dwelt in the cells of the Flustra were animals of a something similar 

 form, though different structure, each crowned with a star-like flower; and the whole 

 together exhaled an odour, when fresh, compared by some observers to that of the 

 orange, by othrrs to that of violets, and, again, to a mixture of the odour of roses and 



