oysters

• oysters

59:2.12There were many va­ri­eties of shell an­i­mals, but their shells were not then so much needed for de­fen­sive pur­poses as in sub­se­quent ages. The gas­tropods were pres­ent in the wa­ters of the an­cient seas, and they in­cluded sin­gle-shelled drills, peri­win­kles, and snails. The bi­valve gas­tropods have come on down through the in­ter­ven­ing mil­lions of years much as they then ex­isted and em­brace the mus­sels, clams, oys­ters, and scal­lops. The valve-shelled or­gan­isms also evolved, and these bra­chiopods lived in those an­cient wa­ters much as they ex­ist to­day; they even had hinged, notched, and other sorts of pro­tec­tive ar­range­ments of their valves.

• oysters

60:2.8The re­turn of the seas im­proved the weather. Corals spread to Eu­ro­pean wa­ters, tes­ti­fy­ing that the cli­mate was still mild and even, but they never again ap­peared in the slowly cool­ing po­lar seas. The ma­rine life of these times im­proved and de­vel­oped greatly, es­pe­cially in Eu­ro­pean wa­ters. Both corals and crinoids tem­porar­ily ap­peared in larger num­bers than here­to­fore, but the am­monites dom­i­nated the in­ver­te­brate life of the oceans, their av­er­age size rang­ing from three to four inches, though one species at­tained a di­am­e­ter of eight feet. Sponges were ev­ery­where, and both cut­tle­fish and oys­ters con­tin­ued to evolve.

• oysters

65:2.5Be­fore long the early sin­gle-celled an­i­mal types as­so­ci­ated them­selves in com­mu­ni­ties, first on the plan of the Volvox and pres­ently along the lines of the Hy­dra and jel­ly­fish. Still later there evolved the starfish, stone lilies, sea urchins, sea cu­cum­bers, cen­tipedes, in­sects, spi­ders, crus­taceans, and the closely re­lated groups of earth­worms and leeches, soon fol­lowed by the mol­lusks—the oys­ter, oc­to­pus, and snail. Hun­dreds upon hun­dreds of species in­ter­vened and per­ished; men­tion is made only of those which sur­vived the long, long strug­gle. Such non­pro­gres­sive spec­i­mens, to­gether with the later ap­pear­ing fish fam­ily, to­day rep­re­sent the sta­tion­ary types of early and lower an­i­mals, branches of the tree of life which failed to pro­gress.