XVI 



LIST OF ILLUSTRATIONS 



FIGURE PAGE 



85. Diaprain of tlio oonjntration of an Int'nsorian 321 



86. Coiijuuration of an Infusorian ........ .323 



87. Dia<,'i-am to illustrate the operation of amphimixis .... 348 



88. Sperm-mother-cells (spermatocytes) of the Salamander . . . 3.50 



89. .\nterior region of the larva of a Mid(,'e 364,393 



90. The Common Shore-Crab, seen from below 367 



91. Hind leg of a Locustid 371 



92. Echinoderm-larvie 387 



93. Pevolopment of a limb in the pupa of a Fly ..... 395 



94. Diagram to illustrate the phylogenetic shifting back of the origins 



of the germ-cells in medusoids and hydroids ..... 412 



95. Diagram to illustrate the migration of the germ-cells in Hydromeduste 414 



COLOURED PLATES 



SOME MIMETIC P.UTTEBFLIES AND THEIR IMMUNE MODELS 



^'•^TE I tofacepage 112 



I'LATF. II „ ,. 114 



Plate 111 „ „ 116 



