174 



SUBJECT INDEX 



Pleodorina, 37, 40 



Pleurobrachia, 76, 84, 86, 89, 116, 117, 



119 

 Podarke, 102 

 Pogonophora, 56, 83, 106 

 Polycelis, 116, 117, 119 

 Polycladida, resemblances to Cteno- 



phora, 90-94 

 Polykrikos, 40 

 Polymeria, 110 

 Polyp, 79, 80, 83, 96, 97 

 Polyphyletic, 13, 152, 153 

 Pomatoceros, 102 

 Porifera, 50, 54-71, 82, 132, 152 

 Porpita, 79 

 Potassium, 140 

 Poterion, 56 

 Primitiveness, 51, 54 

 Proboscidea, 149 

 Protanthea, 82 

 Proterospongia, 57 

 Protostomia, 102-105 



Protozoa, origin, 24-25, 46 



colonial forms, 36-44, 47, 57 et seq. 

 interrelationship, 32-35 

 most primitive, 26, 47 

 syncytia, 44-47 



Protista, 13 



Pterobranchiata, 83 



Radial symmetry, 52, 96 



Radioactive dating of rocks, 137-140 



Rates of evolution, 142-144 



Rhinoscerotoidea, 149 



Rhizoflagellata, 33 



Rhopalura, 72, 75 



Rickettsia, 21-22 



Sabella, 54, 123, 127 



Sabellaria, 116, 117, 119, 123 



Saccocirrus, 102 



Sacculina, 51 



Sakaguchi's test, 120, 121 



Salpa, 87 



Sappinia, 46 



Scolecida, 102 



Scyphozoa, 68, 78, 79, 80, 81, 82, 84, 

 87, 93-96 



Sepia, 117, 118, 119, 120, 126 



Seymouria, 136 



Simplicity, 51 



Siphonophora, 76 



Sipunculus, 114, 117, 118, 127 



Special theory of Evolution, 157 

 Spaer echinus, 121, 126 

 Spiral cleavage, 92, 105 

 Spirochona, 27 

 Spirographs, 116, 117, 123 

 Sponges, origin, 57, 71 



specialised characters, 55-56 



simple characters, 55 

 Spongiaria, 94 

 Sporozoa, 26, 43, 44, 45, 53 

 Stellasterol, 130, 131 

 Sterols, 129-133 



Porifera, 132 



Echinodermata, 129, 133 

 Stichopus, 114 



Stronglylocentrotus, 117, 119, 124 

 Stylotella, 132, 133 

 Suberites, 132 

 Sulphur, 12, 23 

 Symmetry, 52-54, 90, see also Radial 



symmetry; Bilateral symmetry 

 Synapta, 117, 119 

 Syncytia, 39, 44, 46, 63 

 Taurocyamine, 125 

 Taurocyamine phosphate, 125-128 

 Teredo, 103 

 Tetrahymena, 127, 128 

 Tetramitus, 31 

 Tetraplatia, 87, 89 

 Tentaculata, 107 

 Thetia, 126 

 Thiobacillus , 11, 23 

 Thorium, 138 

 Trachylina, 78, 84 

 Trematodes, 72, 94 

 Tricarboxylic acid cycle, 9, 10, 11 

 Trichonympha, 26 

 Trochosphaera, 54 

 Turbellaria, 83, 89-94, 108 

 Tubularia, 76, 77 

 Uranium, 137-139 

 Velella, 79 

 Vermes, 35 

 Vertebrata, 102, 113, 129, 134 et seq., 



153 

 Viruses, 18-21, 151 

 Volvox, 37, 39, 40, 44, 46, 57, 59, 



60-61 

 William of Occam, 9 

 Zoothamnion, 41, 42, 48 



