. The sea-beach at ebb-tide : a guide to the study of the seaweeds and the lower animal life found between tidemarks . s, in no way resembles the adult. When it emerges fromthe egg it is a free and independent animal, with one eye, three pairs of legs, and a single shell. Itswims about for a while and moultsseveral times. It then has two eyes, twoshells, and six pairs of legs. At thisperiod it seeks a permanent home, andattaches its anterior end to the object itselects by means of its antennae, whichhave become suckers. It makes its holdsecure by secreting a cement whichpermanently fastens it
. The sea-beach at ebb-tide : a guide to the study of the seaweeds and the lower animal life found between tidemarks . s, in no way resembles the adult. When it emerges fromthe egg it is a free and independent animal, with one eye, three pairs of legs, and a single shell. Itswims about for a while and moultsseveral times. It then has two eyes, twoshells, and six pairs of legs. At thisperiod it seeks a permanent home, andattaches its anterior end to the object itselects by means of its antennae, whichhave become suckers. It makes its holdsecure by secreting a cement whichpermanently fastens it to the spot, Itthen undergoes metamorphosis, loses its bivalve shell and itseyes, and attains its characteristic cirri/>«/*, or curled featherylegs, and a new shell covering. During these transformations,from the time it be- ^ comes fixed until it at-tains its adult form,the barnacle fasts, liv-ing by the absorptionof its own animal food subsequentlyconsists of the minuteanimal forms whichabound in the sea. Itsfurther growth is bymoulting, but partsonlv of its covering * are disengaged; the ad sc B sk. - m ov Sliell IS peril! ail i ll I. and /.w,(/,,/*. r,. anatomj B, anti nnules; •. ;uli1iiiiii- iimsl» ; 111. \\< onn< w^i\-,. otarvae ..f srut;i ; ICTUM: . Idi; parapet; O», i.\:iry ; ovi, uvi- .inri : .sr. scutum; */,-. parapet . y lines, as in inolhisks. The lining of the shell, or en-veloping skin of the animal, and also the cuticle of the legs are 252 MARINE INVERTEBRATES shed, and in the spring of the year these thin, glossy casts are foundin abundance floating on the surface of the water near the shore. There are but three orders of barnacles, namely, those in whichthe shell is directly attached to the rocks, those which are attachedto floating objects by a long stalk, and those which are parasiticon animals. A species of the third order infests the whale. The older zoologists classed barnacles with the Mollusca, but in1829 Vaughan Thompson
Size: 1734px × 1440px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectmarinea, bookyear1901
