686 



INVERTEBRATA 



Post-oral arms in larva of Asterias, 465 ; of 

 larva of Mi in us esculentus, 508 ; of larva 

 of o/iliiiitliri.'- j'rinjHis, 490 ; of larva of 

 Syniijiln ilii/iiiitii, 533 



Post-oral band of cilia in larva of Asteriax, 

 464 



Post-retinal layer, formation of, in central 

 eyes of A'/i'/cnn, 234 



Prae-oral arms of ciliated band in larva of 

 Asterias, 464 ; in larva of Echinus escu- 

 lentus, 509 ; in larva of Synapta <li<titla, 

 533 ; in New England Tornaria, 576 



Prae-oral band of cilia in larva of Asterinx. 

 464 ; in larva of Phascolosoma, 376 



Prae-oral coelom of Actinotrocha larva, 

 381 



Prae-oral lobe, disappearance of. in Actino- 

 trocha larva, 383 ; of larva of Asterinc 

 gili/iuMi, 473 



Prae-oral loop of ciliated baud in larva of 

 Asferias, 464 ; in larva of >'///'/// 

 il it/ Hutu, 532 ; of New England Tornan;i, 

 576 



Pre-anal spine of Nanplius larva of Cirripedia, 

 202 



Pre-autennae of Scolopendra, 282 



Premandibnlar cavities of Vertebrata, 606 



Preservation of eggs, methods of, for Amplii- 

 u.i-ns l/i iiceoli/l UK, 587; for Antedon rosacea, 

 545: for Asmr/* n/i'i/n/ucephala, 438, 439-; 

 for Astacus, 178, 179 ; and larvae for 

 Astcruiili-a, 458, 459, 460; for Aurelia 

 aurita, 67 ; for Cynthia partita, 609 ; for 

 Donacia, 245 ; for Ltreissensia, 333 ; for 

 Firin/i, 320 ; and embryos and larvae for 

 Grant ia, 38; for Pa fell a, 292; for Phi/*u, 

 320 ; for Polygordius, 129, 130 ; for 

 Sin/ Hlii, 428 ; for Urticina i-r<_i^sii-i,r,iix, 76 



Priapuloidea, 163, 372 



Primary body- cavity, 165; of > larva of 

 Anti'rias, 461 



Primary cerebral ganglion of Astacus, 184 



Primary dorsal organ, formation of, in em- 

 bryo Of hiniiii-iii, 247 



Primary germ-cells, formation of, in Phyllu- 



tf nun in, 262 

 Primary germinal involution of Asterinn 



i/iMiosa, 481 

 Primary gill-slits, formation of, in larva of 



A'nijihiu.i-iix lanceolatus, 590 

 Primary niadreporie pore, formation of, in 



embryo of Anfcifnn rosacea., 547 ; in larva 



of Axli-riii ft, 465 ; in larva of Ophiuthr/.'' 



fragilis, 489 

 Primary mesenchyme, formation of, in larva 



of Echinus esculentus, 507 ; in Ophintli.ri.i- 



fragilis, 486 

 Primary mesoderm, formation of, in Astacus, 



181 

 Primary radial plates, formation of, in 



A ii/i'ilnii riisdi-i'd, 556 

 Primary stomodaeum, formation of, in 



( 'nil ill i mi i nsseola, 422, 423 

 Primary tmchoblasts, formation of, in CV<y</- 



dula, 321 ; in Fiona, 321 ; in 



295 ; in Phascolosoma, 374 

 Primary yolk pyramids of egg of Astern*. 



180 ; of eggs of Scolop* ndra, I'sl 

 Primitive anus, formation of, in 7W////I. /<////.>. 



139 

 Primitive cumulus, formation of, in embryos 



of Arjdcna, 224 ; in embryos of Donacia, 



247 ; in embryos of Pedipalpi, 241 ; in 



embryos of Scorpion, 240 

 Primitive germ-cells, definition of, 2 

 Primitive mouth, formation of, in 7V///- 



ijunUus, 139 

 Primitive streak in eggs of Cephalopoda, 356 ; 



in embryo of Agelena, 223 ; in embryos 



of Pedipalpi, 241 ; in embryos of Pcri- 



patus capensis, 171 ; in embryos of 



Scolopendra, 282 

 Principal retractor muscles of Trochophmv 



larva of Phascolosoma, 376 

 Proboscis, formation of, in CallliUitu ri/ssen/n, 



424 ; in Nemertinea, 123 ; in New England 



Tornaria, 577 

 Proboscis cavity, formation of, in Bulnni,- 



ylossus clariijfriis, 571 

 Proboscis pore, formation of, in Bal'anoglossus 



clavigerus, 572 

 Proboscis sheath, formation of, in Nemertinea, 



123 

 Proctodaeum, formation of, in Aiji-lrmi, 226, 



231 ; in Astacus, 183 ; in Bombyn, 280 ; 



in Callidina russeola, 425 ; in Jtnnai-in. 



253, 254 ; in D-reissensia, 337 ; of larva 



of (ftilt'i -11,-i'lln nlnti, 269 ; in Cyphonautes 



larva of Mcml/ranipora, 390 ; in Pcrfid-llim/ 



i <-l/i in/tit, 400; m Peripatus capensis, 175 

 Progoneata, 280, 281, 285 

 Pronephros, 162 

 Prosobranchiata, 291, 320, 324 

 Protandrons, definition of, 2 

 Protista, 660 

 Proto-annelida, 416 

 Protobranchiata, 349 

 Protocephalic region of embryo of Dmiaciu, 



251 

 Protocerebrum of Astacus, 184 ; of ]>oiu-i</, 



258 ; of Scoloptndm, 283 

 Protochordata, 381 ; development of, 568- 



648 



Protocoelomata, 436 ; denned, 661 

 Protocormic region of embryo of lionacin, 



251 



Protogynons, definition of, 2 

 Protonemertinea, 118 

 Protonephridium of Echiuroidea, 163 ; of 



l'<iliiiii,r<liits, 145 ; of Polygon I i ii. * />/>i-i/- 



diculatus, fate of, 150 ; of Polyy<>r<H<"< 



lacteus, fate of, 152 

 Protostigmata, formation of, in f'in<t intesti 



nafis, 627 ; in larva of Doliolmn, 637 

 Prototracheata, 169, 170 

 Prototroch, of Polifyonfins upjwwliriiltihi*, 



destruction of, 150 ; disappearance of, in 



larva of 1'hascolosoma, 377, 378 ; forma- 



