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 A. E. SHIPLEY, 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 A. E. SHIPLEY, M.A., F.R.S.; =Pentastomida=, by A. E. SHIPLEY, M.A., F.R.S.; =Pycnogonida=, by D’ARCY W. THOMPSON, C.B., M.A.