INDEX 



Names of genera and species are printed in italics. 



The figures in thick type refer to illustrations. 



When the first of several figures after a word is followed by a semicolon 

 it indicates the principal reference to the subject. 



An asterisk (*) signifies that some of the series of figures which immedi- 

 ately follow it refer to particular genera only. 



Reference to the summaries of the characteristics of the groups is only 

 made when information there given is not to be found elsewhere. 



Abambulacral surface, see Aboral 

 surface 



Abdomen, of Arachnida, see Opis- 

 thosoma; of Arthropoda, 271; of 

 Crustacea*, 271, 294, 296, 316, 

 320, 324, 325, 329, 331, 347, 349, 

 355, 358, 360, 362, 373, 374; of 

 Insecta*, 271, 386, 402, 409, 415, 

 423, 426; of lulus, 381; of Poly- 

 chaeta, 237 



"Abdomen" of Tunicata, 596, 598 



Abdominal limbs, of Crustacea*, 

 292-3, 294, 303, 348, 350, 351, 

 355, 359, 368, 373 ; of Insecta, 386, 

 401, 406, 408 ; of lulus, 381 



Abdominal region of Balanoglossus, 

 586 



Aboral aspect, side, or surface, 124; 

 of Echinodermata, 547 



Aboral sinus system, 550, 551, 575 



Acantharia, 71, 75, 76 



Acanthohdella, 267; 228, 263, 266 



Acanthobdellidae, 267 



Acanthocystis, 35 



Acanthonietra, 76 



A. elastica, 77 



Acanthoso?na, 299 



Acarina, 461 



Accessory nidamental gland, 517 



Acephalous larva, 439 



Acerentomum doderoi, 409 



Aciculum, 231 



Acineta, 109; 4, 5 



A. grandis, 5 



A. lemnarum, 5 



Acmaea, 478, 489 



Acmaeidae, 490 



Acoela, 188 



Acontia, 166 



Acrothoracica, 343 



Actaeoti, 491, 494 



Actinia, 164 



A. 7nesetnbryanthemum, 164 



Actitioceras, 528 



Actinometra, 578 



Actinomma, 76 



Actinomyxidea, 95 ; 93 



Actinophrys, 78; 23, 28 n. 



A. sol, 79, 80 



Actinosphaerium , 80; 6, 16, 19, 24, 

 28, 35, 78 



A. eichhorni, 18, 37 



Actinotrocha, 545 ; 546 



Actinozoa, 157; 132 



Actinula, 138 



Actipylaea, see Acantharia 



Adambulacral ossicles, 558 



Adambulacral spines, 558 



Adductor muscles, of Cirripedia, 

 339; of Conchostraca, 317; of 

 Crustacea, 297; of Lamellibran- 

 chiata*, 499, 510; of Leptostraca, 



349 

 Adelea, 85 

 Adoral wreath, 97 

 Aega, 356 

 A. psota, 357 

 Aeolosoma, 259 

 Aeschna, 394 

 A. cyanea, 416 



Aesthetascs, see Olfactory hairs 

 Aesthetes, 476 

 Aflferent branchial vein, 506 

 Aiferent canals, see Inhalant canals 

 Agametes, 32 

 Agamogony, 31 ; 32, 83 

 Agamonts, 31 

 Aggregata, 85 ; 20, 38 

 Alary muscles, 391, 391 

 Alciopidae, 243 



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