IXDKX 



81.3 



Tetrabranchiata, 767*, 760. /70. 771, 



773, 774, 7sd 

 Tetractinellida. lia*. 122 

 Tetrami-ta, 73 

 Tetrrirhi/>i<:/,.i<.i. 256, 257 

 Tetr(i*t<.'nnii<i. 286 

 Thalasto: tun. 479, 481 

 Thalassoplancta, 63 

 Thtca, 202* 



Thomson, J. Yaughaii, 3 

 Thorax, of Apus, 519 : Astacus. 528 : 



Periplaneta, 606 : Solpugida, 648 

 Thread-worms, 292 See Nemathel- 



minth- - 

 Thuricola, 97 

 Tliysanoporlti. 554 

 Thysanoptera, 618* 

 Thysanozoon, 251 

 Thysanura, 615*, 625 

 Ticks, 637, 646 See Acarida 

 Tiedemann's vesicles, 377*. 417 

 Tintinnidium, 96 

 Tissues, 25* 



Tjalfiella. 221. 222, 223, 226 

 Tomopteris, 477 



Tooth-shells, 663 See Scaphopoda 

 Trachete, 36*, 593, 724 

 Trachea! gills, 627, 628 

 Trachea! system (Porpita), 165 

 Tracheliastes, 561* 

 Trachelius, 96 

 Trachelomonas, 73 

 Trachylinse , 142* : General structure, 



154 Sense organs, 154 : Tentacles, 



155 Reproductive organs, 154, 

 155 Development, 155 



Traehymedusse, 142*, 154, 155, 156 



Translation, 280* 



Transverse plane. 210* 



Trap -door Spider, 656 



Trapezia, 207 



Trematoda, 248*, 252, 253, 254, 255, 

 256, 258, 259, 260, 261, 262, 263, 264, 

 265, 266, 267, 268, 272, 273, 274, 278, 

 279, 280, 282, 283 : Example, 236 



Treptoplax, 231 



Triarthrus hecki. 590 



Trichina, 305, 306 



Trichinella, 301, 305, 306 



Trichinella spiralis, 303 



Trichiniasis, 306 



Trichocyst, 91*, 92 



Trichoplax, 231 



Tricho^toaiata, 93 



Tricladida, 248*, 249, 251, 253, 257, 

 259. 262, 204, 266, 271. 278, 279 



Tricosphcerium siebolilii. 50, 51 



Tridacna rjiyas, 692 



Trigger-hair See Cuidocil 



Trigonia, 678, 683, O'tJ 



Trilobita, 589. 590, 591, 660 



Trimorphism, K'.o* 



Tristicothceta, 313 



TRITON RUBICUNDUS, 702 : Shell. 702, 

 703, 704 : Hxtcrnal features of soft 

 parts, 701. 705 : Foot. 705, 706 : 

 Visceral spiral. 7l)(i : Mantle, 706: 

 Cteiiidium, 706: Ospliradiinn, 706: 

 Digestive system, 707, 708, 709 : 

 Vascular system, 7d!, 710, 711 : 

 Excretory system, 711 : Xervous 

 system. '710, 711, 712 : Sensory 

 organs, 712 : Reproductive organs, 

 712, 713 : Systematic position, 715 



TritonidoB, 715*, 725 



Trivium, 370*, 407 



Trochal disc, 318* 



Trochelminthes, 31G* : Appendix, 330 



Trocheta, 504 



Trochophore See Trochosphere 



Trochosphcera, 322, 325, 326, 328 



Trochosphserida, 322* 



Trochosphere, 316. 430 



Trochus, 714, 727 



Trombidium fiiliginosum, 649 



Trophozoite, 82 



Trypanosomes, 72, 74 



Tube-feet. 369, 370*, 387, 388, 393 



Tubifex, 461, 471 



Tubificidce, 476 



Tubipora, 193, 195, 196, 197, 200, 201, 

 205, 208 



Tubularia, 145, 153 



Tubularice, 143, 145 



Turbellaria, 248*, 251, 252, 253, 257, 

 259, 260, 261, 262, 263, 264, 265, 266, 

 278, 282 : Example, 233 



Turbo, 714, 727 



Tympanic nerve -endings, 630* 



Tympanum, 630* 



Typhlosole, 447*, 464, 66S 



U 



Umbo, 664, 665 



Umbrella, 169* 



Uncus, 319* 



Undulating membrane, 74*, 94, 95, 96 



Unicellular animals, 20* 



Unicellular gland, 26* 



Unio, 662, 678 See Anodonta 



Unio marijaritifcra , 662, 692 



Unionid i , 678* 



Unisexual, 40* 



Urea, 37 



Uric acid, 13, 37 



Urinary bladder, (171* 



Urinary organs, 37* 



Urnatelln, 347, 34 s 



Urns, 487* 



Urocceles, 67 1 * 



Uropods, 530* 



Uterine bell, 309 



Uterus, 40* 



