674 



INVEETEBEATA 



Determinate cleavage, 416 

 Deuterocerebrumof Astacus, 184; of Donacia, 



258 ; of Scolopendra, 283 

 Deuteroplasin, 19 ; definition of, 3 

 Deutovum of Mites, 242 

 Development of larva of Dentaliitm, deprived 



of first polar lobe, 330 ; deprived of second 



polar lobe, 331 



Dexiotropic cleavage, definition of, 104 

 Diakinesis, definition of, 6 

 Diminution of the chromatin in segmenting 



egg of Ascaris megalocephala, 440 

 Dinophilus, egg of, 11 

 Dipleurula larva, 561, 564 ; definition of, 



560 ; interpretation of, 661 

 Diplopoda, 280, 281 ; development of, 284 

 Diplosomidae, 637 ; development of, buds 



of, 642-644 

 Dipnoi, 569 

 Diptera, 245, 272, 279 

 Directive mesenteries, definition of, 83 

 Disc of fixed larva of Asterias, 469 

 Discocoelis, 107, 109 

 Distaplia, 634, 638, 640, 641, 644 

 Dolichoglossus, 575, 584, 605 

 Dolichoglossus kowalevskii, 569 ; development 



of, 582, 583 

 Dolichoglossus pusillus, 570 ; development 



of, 583 

 Doliolum, 639, 640, 641 ; development of, 



636, 637 



Donacia, 261, 263, 265, 266, 267, 272 

 Donacia crassipes, development of, 245-260 

 Dondersia, 325 

 Dorsal aorta, formation of, inAgelena, 229 ; 



in Amphioxus lanceolatus, 595 

 Dorsal arch in skeleton of larva of Echinus 



esculentus, 509 

 Dorsal blood-vessel, formation of, in Clepsine, 



163 ; in Echinus esculentus, 518 

 Dorsal cell family in segmenting egg of 



Ascaris megalocephala, 440 

 Dorsal chamber of Urticina crassicornis, 80 

 Dorsal ciliated epaulettes, formation of, in 



larva of Echinus esculentus, 511 

 Dorsal cord, formation of, in embryo of 



Phascolosoma, 376 



Dorsal curvature of embryo of Donacia, 259 

 Dorsal muscle of Cyphonautes larva, 390, 392 

 Dorsal nerve-cord, formation of, in Dolicho- 



gJossus kowalevskii, 583 ; in New England 



Tornaria, 578 

 Dorsal nerve-tube, formation of, in New 



England Tornaria, 578 

 Dorsal organ, formation of, in Amphiura 



squamata, 500 ; in Asterina gibbosa, 480 ; 



in embryo of Pedicellina, 400 ; in embryo 



of Scolopendra, 284 

 Dorsal retractor muscles, formation of, in 



larva of Dreissensia, 341 

 Dorsal sinus, formation of, in Nephelis, 163 

 Dorse-central plate, formation of, in Am- 

 phiura squamata, 499 ; in Asterina gibbosa, 



478 



Dorso-lateral chamber of Urticina crassi- 

 cornis, 80 



Dorso-lateral spine of Nauplius larva of 

 Cirripedia, 201 



Dorso-ventral muscles of Yungia, 114 



Doryphora, 267, 277 ; development of wings 

 of, 271-273 



Doryphora decemlineata, development of, 

 245, 246, 247 ; embryonic development 

 of, 261 



Doubly fertilized eggs of Ascaris megalo- 

 cephala, development of, 451-453 



Dreissensia, 349, 350 



Dreissensia polym&rgha, development of, 

 332-348 



Dytiscidae, 273 



Dystiscv.s marginalis, development of eyes of, 

 273-277 



Ear, formation of, in larva of simple 

 Ascidian, 620 



Ecardines, 407, 414 



Ecdysis in Astacus, 185 



Echinocardium cordatum, 504, 523 ; develop- 

 ment of, 522 



Echinocyamus pusiUus, 504, 522 



Echinodermata, 110, 287, 408, 416, 418, 

 435, 573, 585, 586, 589, 600, 645, 653, 

 657, 659, 660, 662 ; development of, 

 456-567 ; development of unfertilized eggs 

 of, 17 ; eggs of, 3 ; experiments on eggs 

 of, 30 ; fossil representatives of, 20 ; 

 larva of, 19 



Echinoidea, 287, 456, 461, 464, 482, 484, 

 530, 531, 538, 541, 542, 543, 544, 560, 

 562, 564. 565, 570, 571, 653 ; develop- 

 ment of, 504-529 



Echinopluteus, 280, 527, 532, 533, 551, 560, 

 565, 573 ; definition of, 490 ; description 

 of, 508, 509 



Echinus, 228, 463, 484, 505, 590, 653, 654 ; 

 entelechy of, 21 



Echinus esculentus, 504, 505, 523, 529 ; 

 development of, 506-522 



Echinus microtuberculatus, 504, 505 



Echinus miiiaris, 504, 516, 523 



Echinus-rudiment of larva of Echinus escu- 

 lentus, formation of, 513 



Echiuroidea, 163, 372 



Echiurus, 167 



Ectoderm, definition of, 53 ; formation of, 

 in Cerebratulus hicteus, 119 ; in Jin-nada, 

 249; in Pcripiititx capcnsis, 170; in 

 Planocera, 105 ; in Tubularia, 55 



Ectodermal origin (supposed) of mid -gut in 

 Insecta, 262 



Ectodermal vesicles in larva of DdUoliuin, 

 637 



Edwardsia stage in development of Urticina 

 crassicornis, 83 



Edwardsiae, 53, 86 ; arrangement of mesen- 

 teries of, 83 



Eggs of Amphioxus lanceolatus, 586, 587 ; 

 of Amphioxus lanceolatus, deliisceuce of, 



