cuttlefish

• descendant of cephalopods

59:2.11Lime-se­cret­ing al­gae were wide­spread. There ex­isted thou­sands of species of the early an­ces­tors of the corals. Sea worms were abun­dant, and there were many va­ri­eties of jel­ly­fish which have since be­come ex­tinct. Corals and the later types of sponges evolved. The ceph­a­lop­ods were well de­vel­oped, and they have sur­vived as the mod­ern pearly nau­tilus, oc­to­pus, cut­tle­fish, and squid.

• cuttlefish

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.

• oxygenate blood with copper

65:6.4One of the most ser­vice­able and com­plex episodes in the evo­lu­tion of the higher types of an­i­mals con­sisted in the de­vel­op­ment of the abil­ity of the iron in the cir­cu­lat­ing blood cells to per­form in the dou­ble role of oxy­gen car­rier and car­bon diox­ide re­mover. And this per­for­mance of the red blood cells il­lus­trates how evolv­ing or­gan­isms are able to adapt their func­tions to vary­ing or chang­ing en­vi­ron­ment. The higher an­i­mals, in­clud­ing man, oxy­genate their tis­sues by the ac­tion of the iron of the red blood cells, which car­ries oxy­gen to the liv­ing cells and just as ef­fi­ciently re­moves the car­bon diox­ide. But other met­als can be made to serve the same pur­pose. The cut­tle­fish em­ploys cop­per for this func­tion, and the sea squirt uti­lizes vana­dium.