INDEX. 



6I 7 



Pipidce, 390. 



Pisces, 337, 338; general characters of, 

 340 ; scales of, 340 ; skeleton of, 341- 

 345; limbs of, 345; tail of, 348; diges- 

 tive system of, 351 ; respiratory system 

 of, 349 ; heart of, 350 ; swim-bladder of, 

 351 ; nervous system of, 352 ; repro- 

 ductive system of, 352 ; orders of, 353- 

 377 ; distribution of, in time, 377-380. 



Placenta, 472, 484. 



Placentalia (Mammalia), 484. 



Placodus, 419. 



Placoganoidei, 367, 368, 378. 



Placoid (scales of Fishes), 341, 370. 



Placoidei, 370. 



Plagiaulax, 560, 562. 



Plagiostomi, 370, 371 ; characters of, 372- 

 374. 



Planarida, 166, 167, 176. 



Planorbis, 289, 296. 



Plantigrada, 531, 534. 



Planula, 101. 



Plastron, 398, 399. 



Plataleadce, 450. 



Platanista, 511. 



Platyelmia, 158, characters of, 159. 



Platyrhina, 552, 554. 



Plecotus, 548. 



Plectognathi, 363. 



Pleswsauria, 417. 



Plesiosaurus, 418. 



Pleura, of Lobster, 194 ; of Trilobite, 209. 



Pleur acanthus, 380. 



Pleurobrachia, 124; ctenophores of, 125; 

 canal system of, 125, 126 ; development 

 of, 127 ; homologies of, 127. 



Pleurobrachiadce, 128. 



Pleurobranchiadoe, 292, 296. 



Pleurobranchus, 296. 



Pleuronectidce, 362, 373. 



Pleuronema, 72. 



Pleurotoma, 294. 



Pleurotomaria, 295. 



Ptiolophus, 564. 



Pliopithccus, 568. 



Plotus, 446. 



Plough-share bone, 427. 



Plumaster, 157. 



Plurnularia, 87.' 



Pluteus, 137, 138. 



Pneumatic filaments of Physophoridce, 93. 



Pneumatocyst, 92. 



Pneumatophore, 92, 93, 94. 



Pneumodermon, 298. 



Podophthalmata, 198; characters of, 213. 



Podosomata, 225. 



Podura, 235, 242. 



Polyarthra, 175. 



Pblycoelia, 133. 



Polycystina, 58, 59. 



Polydesmus, 232. 



Polygastrica (of Ehrenberg), 67. 



Polynoe, 186. 



Polypary, 77, 81. 



Polype, 110. 



Polypide, 259, 260. 



Polypidom, 77. 



Polypite, 77. 



Polypterus, 367. 



Polystome Infusoria, 71. 



Polythalamia (Foraminifera), 52. 



Polytrema, 56. 



Polyxenia, 97 



Polyzoa, 253, 254, 255 ; characters of, 258- 

 265 ; distinctions from Hydrozoa, 258, 

 259 ; typical polypide of, 260 ; avicularia 

 of, 261 ; lophophore of, 263 ; nervous 

 system of, 263 ; digestive system of, 263 ; 

 reproduction of, 264; statoblasts of, 

 264 ; development of, 265 ; relations to 

 Tunicata, 269 ; divisions of, 265 ; orders 

 of, 265 ; distribution of, in space, 275; in 

 time, 276. 



Polyzoarium, 258, 259. 



Pontobdella, 188. 



Porambonites, 274. 



Porcellanous shells, 256, 



Porcellia, 313. 



Porcupine, 544. 



Pores of Sponges, 60, 61. 



Parties, 132. 



Poritidce, 134. 



Porpoise, 505, 510. 



Portuguese man-of-war, 76, 89, 93. 



Potamides, 295. 



Poulpe, 302, 305. 



Praya, 91. 



Prayidce, 92. 



Pressirostres, 448, 450. 



Prestwichia, 220. 



Priapulacea, 179. 



Pristis, 374. 



Proboscidea, 484, 487 ; characters of, 527; 

 distribution of, in time, 566, 567. 



Proboscis, of Medusae, 96 ; of Crinoidea, 

 149; of Planarida, 167; of Acantho- 

 cephala, 168 ; of Gephyrea, 178 ; of 

 Errantia, 186 ; of Lepidoptera, 236 ; of 

 Proboscidea, 527. 



Procellaridce, 445. 



Proccelia (CrocodUia), 414, 415. 



Procyon, 535. 



Producta, 275. 



Production, 275, 276. 



Proglottis, 160. 



Pro-legs, 249. 



Promeropidce, 462. 



Pro-ostracum, 306, 307. 



Propodite, 196. 



Propodium, 287, 293. 



Proscolex, 161, 162. 



Prosimice, 553. 



Prosobranchiata, 291: divisions of, 291, 

 294. 



Prosoma, 299, 307. 



Prosoponiscus, 220. 



Prostomium, of Planarida, 167 ; of An- 

 nelides, 180. 



Protaster, 157. 



Proteles, 538. 



Proteolepas, 204. 



Proteus, 336, 385, 390. 



Proteus-animalcule, 47. 



Prothorax, 234. 



Protoplasm, 4. 



Protopodite, 196. 



Protopteri, 375 (see Dipnoi). 



Protornis, 469. 



Protovirgularia, 133. 



Protozoa, 14 ; general characters of, 42, 

 43 ; classification of, 43, 44. 



Proventriculus, of Earthworms, 183 ; of 

 Birds, 434. 



Proximal, 77. 



