INDEX 



691 



Thecidium mediterraneiim, 407 



Thecoida, 456 



Thoracic region of embryo of Donacia, 251 



Thoracico-abdominal rudimeiit in embryo of 

 Astacus, ISO 



Thysanura, 245, 287, 288 



Tiara, medusa of, 59 



Tip-cells of Molluscan cross in embryo of 

 Crepidula and Fiona, 321, 322 ; in em- 

 bryo of Patella, 294, 297 



Tipulidae, 278 



Tongue -bars, formation of, in Amphioxns 

 fmiceoliitiis, 604 ; in New England Tor- 

 uaria, 579 



Tornaria, 1, 569, 582, 585, 605, 606 ; of 

 Jii//n, /, i : ///is.^i/\ d<n-i<ji'rns, 574 ; develop- 

 ment of, of Nassau, 579-581 ; New Eng- 

 land, 574-579; of Pacific Coast, 581, 

 582 ; interpretation of, 661 



Torsion of larva of A cmaea, 304 ; of embryo 

 of Paludina, 315, 316 ; of larva of Patella. 

 300 



Tracheae, formation of, in Agelcna, 231 ; in 

 Donacia, 258 ; in wings of Doryphora, 273 ; 

 iu Peripatus capensis, 175 



Tracheoles in wings of Doryphora, 273 



Trachymedusae, 53 ; development of, 67 



Transverse ciliated rings, formation of, in 

 larva of Antedon rosacea, 546 ; in larva of 

 Cucumaria planci, 542 ; in larva of 

 Synapta digitata, 536, 537 



Transverse commissures, formation of, in 

 nervous system of Astacus, 185 



Trematoda, 102, 103 



Triaxouia, 37 



Triclada, 102, 103 



Trilobita, 169, 205, 238, 244, 285, 286 



Trilobite larva of Limnlus, 238 



Tritocerebrum of Astacus, 184 ; of Donacia, 

 258 ; of Scolopendra, 283 



Trochal disc, formation of, in Callulina rus- 

 seola, 424 



Trochophore larva, 390, 405, 406, 408, 411, 

 415. 416, 427, 561, 655, 661 ; interpreta- 

 tion of, 164 ; of Acmaea, 320 ; of Annelida, 

 description of, 130, 368 ; of Annelida, 

 compared to Nauplius, 204 ; of Dental i inn, 

 328 ; of Dondersia, 325 ; of Dreissensin, 

 337, 338, 368 ; of Eupomatus, 154 ; of 

 Fissurella, 320 ; of Haliotis, 320 ; of 

 Paludina, 310 ; of Patella, 298, 368 ; 

 of Phascolosoma, 370 ; of Polygordius, 

 139 ; of Polyplaeophora, 320 ; of Sipuncu- 

 loida, 163, 372 ; of Trochus, 320 

 Trochus, 320, 322, 323 



Trophi, formation of, iu Cllidinn russeola, 

 424 



Trophocyte of bud of Ephydatia, 48 



Trophozooids of Doliolnm, 640 



Trunk blastema, formation of, in the embryo 



of Nephdis, 162 ; in the embryo of 



Phascolosoma, 375 ; in the larva of /'"f//- 



fjurdius, 142 



Truuk-coelom, formation of, in A H/JI/H'< >.'"< 



lanceolatus, 592 ; in Balanoglossus dam- 

 gems, 574 ; in Actinotrocha larva of I'lmr- 

 oitis, 381 ; in New England Tornaria, 575 



Tubal cells of archiuephridia in Polyijui'diim, 

 140 



Tube-feet, formation of, in Asterias, 471 ; in 

 Asterina gibbosa, 476 ; in C/ici/i/inria 

 planci, 542 ; iu Echinus esculentus, 514, 

 517 ; in Ophioth //.-. fmyi/ix, 493, 495 



Tubularia, 60, 61, 62, 383 ; development of, 

 54-69 



Tubularia indivi-sa, 54 



Tubularia mesembryanthcmum., 54 



Tunicata, 406, 413, 564, 568, 659, 662, 

 development of, 608-646 



Turbellaria, 102 



Turret cells in segmenting eggs of Gastro- 

 poda, 322 



Umbrella, 324 



Umbrella cavity, vestigial character of, in 



gonophore of Clam, 62 ; in gouophore of 



Sertularia, 62 ; formation of, in medusa 



of Tubularia, 57 

 Under-basal plates, formation of, in Amplii- 



ura squamata, 499 ; in Antedon rosacea, 



548 ; union of, in Antedon rosacea, 558 

 Uuderlip, formation of, in L'o/liiH /m russeola, 



423 



Unio, embryonic development of, 351 

 Uuiouidae, 349, 350, 351, 353, 655 

 Upper sclerotomes, formation of, in larva of 



Amphioxus lanceolatus, 599 

 Ureter, formation of, in Asfactis, 188 ; in 



Dreissensia, 344 ; in Paludina, 314 

 Urnatella, 398 

 Urochorda, see Tunicata 

 Urodela, 656, 657 

 Urticina crassicornis, 85 ; development of, 



76-83 

 Uterus of A scar is megalocephala, 438 



Vagina in Ascaris megalocephala, 438 ; forma- 

 tion of, in Pedicellina echinata, 401 



Valeriauic acid, \ise of, 18 



Valve of intestine, formation of, in larva of 

 PuJi/ijoi-dius, 143 



Vas deferens in Ascfiri* megalocephala, 438 ; 

 formation of, iu Molyula, 628 ; in tii<jitt 

 blpunctata, 434 



Vegetative pole of the egg denned, 26 



Velella, 64 



Veliger larva, 416 ; of l^ntnliinn, 329 ; of 

 Dreissensia, 338 ; of Gastropoda, 369 ; of 

 Paludina, 310 ; of PM/,,. 300 ; of Fele- 

 cypoda, 369 ; of Seapliopoda, 369 



Velum, formation of, in larva of (_'rfj>iitnl<t, 

 321 ; in larva of l>>'iil'tli>nn, 329 : in larva 

 of />(V/,v.sr//.s/c, 3:J8 ; in larvn of /'/"/</, 

 321 ; in larva of rtrll, :!00 ; in larva 

 of Protobranchiata, 319 ; in mtdusa of 

 Tiiliulid-ia, 58 



Vena cava, formation of. in L'/i;/", 362 



Ventral blood- \v^ul, formation of, in 

 x, 518 



