684 



IN VERTEBRA T A 



Pachynema, definition of, 4 

 Pachytene threads, definition of, 4 

 Paguridae, 216 



Paired tube-feet, formation of, in Asterias, 

 471 ; in Asterina gibbosa, 477 ; in Cucit- 

 i/inria p/itnci, 542; \\iEcliinusesculentiis, 

 517 ; (tentacles) in OphiothrLc fragilis, 

 495 



PalatmoH, 192, 243 



Pali, formation of, in Caryophyllia cyathus, 88 

 Palinurus, 214 

 I'nlltne, development of, 243 

 Pallial budding in Urochorda (Botryllidae), 



637 



Paludina, 319, 323, 335, 383, 415 ; de- 

 velopment of, 309-318 

 Pantopoda, 169, 285 ; development of, 242, 



243 



Paragaster of Sycandra raphanus, 43 

 Paragastric canals, formation of, in Beroe, 



94 ; of Cteuophora, 561 

 Paraneuroptera, 245, 272, 277 ; embryonic 



development of, 266 

 Parasyndesis, definition of, 4 

 Parenchyma, formation of, in Nephelis, 163 ; 

 definition of and formation of, in Plano- 

 cera, 168 

 Parenchyma-like tissue of larva of Berfie, 93, 



95 



Parthenogenetic ovuin(a), definition of, 2 

 Patella, 304, 310, 314, 317, 319, 321, 322, 

 323, 330, 332, 334, 335, 341, 375 ; de- 

 velopment of, 291-303 

 I'ufd/a. , -,,1'r/ilea, 291, 292 

 Patella rulgata, 291, 303 

 Pauropoda, 280, 281 

 Pea-plant, self- fertilized, 18 

 Pea-plants result of crossing, 1 6 

 Pecten, 348 



Pectines of Scorpion, formation of, 241 

 Peetinibranchiata, 291 

 Pedal disc, formation of, in Urticina crassi- 



cornis, 81 



Pedal ganglia, formation of, in Dental ium, 

 329 ; in Dreissensia, 342 ; in Loligo, 358 ; 

 in Palndi.na, 315 ; in Patella, 301 

 Pedicellariae of Echinus esculentus, forma- 

 tion of, 515 

 J'edicel/itia, echinata, development of, 398- 



403 



Pedipalpi, 221, 241 

 Pelarjia, development of, 72, 73 

 Pelecypoda, 291. 463 ; ancestors of, 368, 



369 ; development of, 332-353 

 Pelmatozoa, 456, 560, 564 

 Penaeidea, 177, 203, 208, 213 

 Penaeus, 655 ; Nauplius of, 22 

 Penetration path of spermatozoon in egg of 



Cynthia partita, 611 

 /'in /in r/a, 61 



Pentacrinoid larva of Anledon rosacea, 558 

 Pentacrinus, 558, 559 

 Pentacula, definition of, 539 

 Pentastomida, 221 242 



Peracarida, 177, 219 



Pericardial cavity, formation of, in Astacus, 

 187 



Pericardial sac, formation of, in Chiton polii, 

 320 ; in embryo of Paludina, 311 



Pericardial septum, formation of, in ])nnacia, 

 257 ; in Peripatus cape n sis, 174 ; in 

 Phyllodromia, 263 ; in Scorpion, 241 



Pericardium, formation of, in dona in- 

 testinalis, 626 ; of Cyclas, 350 ; in Dnllcho- 

 glossus kou'alevskii, 583 ; in Dreissensia, 

 344 ; in Loligo, 362 ; in Paludina, 314 ; 

 in Peripatus capensis, 174 ; in Cyatho- 

 zooid of Pyrosoma, 634 ; in Scorpion, 241 ; 

 in New England Tornaria, 575 ; in Unio, 

 353 



Perihaemal ring -canal, formation of, in 

 Oph tilth r LI- fragilis, 494 



Perihaemal spaces, formation of, in Asterina 

 yibbosa, 474 ; in Opln'urn brcrispina, 502 



Peri-oral coelom, formation of, in Asterias, 

 469 ; in Asterina gibbosa, 474 ; in Ophio- 

 thri.: 1 fragilis, 497 ; in larva of Synapta 

 digitata, 536 



Peripatus, 157, 187, 190, 204, 230, 232, 

 241, 244, 254, 257, 258, 261, 281, 283, 

 285, 287 



Peripatus capensis, 167, 177, 657 ; develop- 

 ment of, 170-176 



Peripatus novae-zelandiae, 226 



Peripheral rosettes, formation of, in segment- 

 ing eggs of Gastropoda, 322 ; in seg- 

 menting eggs of Phascolosoma, 374 



Periplasm of egg of Agelena, 222 



Periproct, formation of, in Echinus esculentus, 

 518 



Perisarc, formation of, in Tubularia, 57 



Peristome, formation of, in shell of Acmaea, 

 304 ; in shell of Fissurella, 305 ; in shell 

 of HaUotis, 305 



Periviseeral cavity, formation of, in Peri- 

 pi/tiis capensis, 174 



Permanent anus, formation of, in Polygordius, 

 140, 142, 144 



Perophnra, 638, 644 



Per-radial lobe of stomach of Aurelia, 71 



Phalliisi.t, 609, 631 



riiiilliixin iiitiiiniiillata, 619 



Pharynx, formation of, in Agelena, 235 ; in 

 Amphioxus lanceflatiis, 596 ; in larva of 

 < 'if nthia partita, 614; in larva of Doliolum, 



637 ; in Cyathozooid of Pyrosoina, 634 ; 

 in Xalpa, 636; in blastozooid of Urochorda, 



638 ; in Yungia, 114 



l'l,<iscol<>*"nii/, 385 ; development of, 372-380 



I'liiiM'iiliitinina gonldii, 373 



Phascolosmna rnlgnre, 373 



Pholas, 348 



Phoronide'a, 372 ; development of, 380-385 



Phoranis, 406, 560 ; development of, 380- 



385 



Phorozooids of Doliolum, 641 

 Phosphorescent organs, formation of, in Pyro- 



soma, 632 



