222 INVERTEBRATE PALAEONTOLOGY 



Orthoceras, 85, 148, 169, 211 

 Orthodontiscus , 145 

 Orthogenesis, no 

 Orthonota, 146 

 Orthotetes, 165 

 Ostracoda, 32, 83 



mesozoic, 194 



proterozoic, 152 

 Ostrea, 40, 188, 204 

 Ostreidae, 32, 87, 167 

 Oxfordian, 45 

 Oxynoticeras, 191 



Pachy discus, 105, 193 

 Pachypora, 159 

 Packing, 57 

 Palaeechinus, 139, 163 

 Palaeoconcha, 145, 167, 187 

 Palaeocorystes, 194 

 Palaeocyclus, 130 

 Palaeo discus, 139 

 Palaeontography, 4 

 Paludina, 191 

 Panope, 205 

 Paphia, 205 

 Parabolineila, 151 

 Paradoxides, 151 

 Parallelodon, 167 

 Parasalenia, 201 

 Parasmilia, 178 

 Parkena, 179 

 Parkinsonia, 105, 192 

 Parthenogenesis, 115 

 Patella, 147, 205 

 Peat, 28, 39 

 Pecten, 34, 168, 204 

 Pectinidae, 188 

 Pectinirhombs, 135 

 Pedalion, 187 

 Pelagic zone, 86 

 Pelanechinus, 182 

 Pelecypoda, 32, 34, 39, 43, 64 



cainozoic, 203 



deuterozoic, 167 



mesozoic, 187 



morphogeny, 97 



proterozoic, 144 

 Pelmatozoa, 133 

 Peltastes, 182 

 Pennine Uplift, 156 

 Pentacrinus, 31, 179 

 Pentamems, 31, 142 

 Pentre mites, 161 



Perforata, 159 

 Periechocrinus, 137 

 Periods, 77 

 Perischodomus, 163 

 Perischoechinoidea, 100, 108, 



162 



Perisphinctes, 192 

 Permian, 31, 156 

 Perna, 187, 204 

 Pernidae, 105, 167 

 Peronoceras, 80, 192 

 Petalocrinus, 138 

 Petraia, 130 

 Petrifaction, 12, 17, 44 

 Petrifying springs, 12 

 Phacopidae, 152, 171 

 Phacopidella, 152 

 Phaenoschisma, 161 

 Pharetrones, 178 

 Phillips, 69 

 Phillipsastraea, 159 

 Phillip sia, 171 

 Pholadellidae, 168 

 Pholadomya, 189, 204 

 Pholas, 87, 1 68 

 Phormosoma, 182 

 Phylactolaemata, 139 

 Phyllite, 21 

 Phyllocarida, 153 

 Phylloceras, 192 

 Phylogeny, 15, 90, 114 

 Phymosoma, 182 

 Physiography, 80 

 P ileus, no 

 Pinacoceras, 191 

 Pinna, 204 

 Pisania, 206 

 Pisocrinus, 137 

 Pitting, 1 8 

 Placocystis, 134 

 Placopsilina, 127 

 Plagiostoma, 189 

 Plankton, 87 

 Planorbis, 207 

 Platyceras, 147 

 Platycnnus, 161 

 Platyschisma, 147, 168 

 Plectambonites, 142 

 Plectprthis, 142 

 Plesiechinus, 94, 98, 182 

 Pleurodictyum, 160 

 Pleuromya, 189 

 Pleurophoms, 168 



