GENEEA AND GEOTJPS OF THE ECHHirOIDEA. 



309 



Oolopygus, 185. 

 Opechintis, 108. 

 Opisopneustes, 244, 304. 

 Opissaster, 229. 

 Oriolampas, 194. 

 Ornithaster, 236. 

 Orthechimis, 305. 

 Orthocidaris, 33. 

 Ortholophus, 100. 

 Orthopsinse, 59, 80. 

 Ortliopsis, 80. 

 Oviclypeus, 179. 

 Oviilaster, 273. 



Pachyclypeus, 142. 

 Palisechinoidea, 4, 5, 7. 

 Palaeechinus, 13. 

 Palseobrissus, 268. 

 PalcBOcidaris, 9, 11. 

 PalcBodiscus, 18, 20. 

 Palseolampas, 194. 

 PaliBopneustes, 223, 257. 

 Palisostoma, 278. 

 Palseotropus, 273. 

 Paradoxechiuus, 101. 

 Paralampas, 184. 

 Parapygiis, 183, 305. 

 Parasalenia, 119, 120. 

 Paraster, 235. 

 Pedina, 72. 

 Pedininffi, 59, 72. 

 Pedinopsis, 68. 

 PelanecliininEe, 41. 

 Pelanechinus, 41. 

 Peltastes, 45. 

 Periaster, 233, 234. 

 Pericosmus, 232. 

 Perionaster, 229. 

 Peripnenstes, 255. 

 Perischocidaris, 10. 

 Perischodomus, 10. 

 Perisehoeohinoida, 8. 

 Peronella, 156. 

 Peronia, 82. 

 Petalaster, 200. 

 Pholidocidaris, 18. 

 Phormosoma, 42, 310. 

 Phyllacanthus, 28, 32. 

 Phyllobrissus, 187. 

 Phylloclypeus, 192, 194. 

 Pliymechinus, 69. 

 Phymosoma, 86. 

 Pileus, 136. 

 Placodiadema, 64. 

 Plagionotics, 243. 

 Platybrissus, 222. 

 Plesiauthvis, 154. 

 Plesiaster, 294, 305. 

 Plesiocidaroida, 19, 

 Plesiodiadema, 56, 64. 



Plesiolampas, 193. 

 Plesiospatangidse, 199. 

 Pleurechinus, 107. 

 Pleurodiadema, 66. 

 Pliolampas, 294, 305. 

 Plistophyma, 71. 

 Podocidaris, 96. 

 Polycidaris, 34. 

 Polycyphus, 79. 

 Polyporina3, 121. 

 Poroeidaris, 32. 

 Poropeltis, 46. 

 Pourtalesia, 284. 

 Pourtalesiidse, 279. 

 Prenaster, 235. 

 PrionechinuB, 134. 

 Progonechinus, 84. 

 Protoechinus, 13. 

 Prymnadetes, 217, 224. 

 Prymnodesmia, 217, 239, 273. 

 PBammechinus, 127. 

 Pseudasterostoma, 203. 

 Pseudholaster, 294, 305. 

 Pseudoboletia, 123. 

 Peeudocidaris, 51. 

 Pseudodesorella, 190. 

 Pseudodiadema, 57, 60, 61. 

 Pseudopedina, 72. 

 Pseiidopygaulus, 200. 

 Pseudosalenia, 46. 

 Pygaster, 137. 

 Pygastrides, 138. 

 Pygaulus, 171. 

 Pygopiste.% 294, 305. 

 Pygorliynchus, 182. 

 Py gurus, 189. 

 Pyrina, 172. 



RacMosoma, 294, 305. 

 Radiocyphus, 305. 

 Ehabdocidaris, 27, 31. 

 Ehinobrissus, 246, 258. 

 Rhoechinus, 14. 

 Rhyncbopygus, 182. 

 Rotula, 163. 

 Rotuloidea, 148. 

 Bumphia, 156. 

 Runa, 147. 



Salenia, 47. 

 Saleniidte, 45. 

 Salmacis, 109. 

 Salmacopsis, 110. 

 Sarsella, 263. 

 Savignia, 78. 

 Scbizaster, 234. 

 Sohleinitzia, 27, 33. 

 Scutella, 158. 

 Scutellidse, 157. 

 Scutellina, 145. 



