VOLUME IV.

CRUSTACEA, by GEOFFREY W. SMITH, M.A., and the late W. F. R. WELDON, M.A.; TRILOBITES, by HENRY WOODS, M.A.; INTRODUCTION TO ARACHNIDA, AND KING-CRABS, by Sir A. E. SHIPLEY, G.B.E., M.A., F.R.S.; EURYPTERIDA, by HENRY WOODS, M.A.; SCORPIONS, SPIDERS, MITES, TICKS, ETC., by CECIL WARBURTON, M.A.; TARDIGRADA (WATER-BEARS), by Sir A. E. SHIPLEY, G.B.E., M.A., F.R.S.; PENTASTOMIDA, by Sir A. E. SHIPLEY, G.B.E., M.A., F.R.S.; PYCNOGONIDA, by D'ARCY W. THOMPSON, C.B., M.A.

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