I XI) EX 



815 



Tetrabranchiata, 767*, 769, 770, 771, 



773, 774, 780 

 Tetractinellida, 113*, 122 

 Tetramita, 73 

 Tetrarhynchus, 256, 257 

 Tetrastemma, 286 

 Thalassema, 479, 481 

 Thalassoplancta, 63 

 Theca, 202* 



Thomson, J. Vaughan, 3 

 Thorax, of Apus, 519 : Astocus, 528 : 



Periplaneta, 606 : Solpugida, 648 

 Thread-worms, 292 See Nemathel- 



minthcs 

 Thuricola, 97 

 Thysanopoda, 554 

 Thysanoptera, 618* 

 Thysanozoon, 251 

 Thysanura, 615*, 625 

 Ticks, 637, 646 See Acarida 

 Tieclemann's vesicles, 377*, 417 

 Tintinnidium, 96 

 Tissues, 25* 



TjalfleUa, 221, 222, 223, 226 

 Tomopteris, 477 



Tooth -shells, 663 See Scaphopoda 

 Tracheae, 36*, 593, 724 

 Tracheal gills, 627, 628 

 Trachea! system (Porpita), 165 

 Tracheliastes, 561* 

 Trachelius, 96 

 Trackelomonas, 73 

 Trachylinee , 142* : General structure, 



154 : Sense organs, 154 : Tentacles, 



155 : Reproductive organs, 154, 

 155 : Development, 155 



Trackymedusge, 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 becki, 590 



Trichina, 305, 306 



Trichinetta, 301, 305, 306 



Trichinella spiralis, 303 



Trichiniasis, 306 



Trichocyst, 91*, 92 



Trichoplax, 231 



Trichoitomata, 93 



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

 259 ? 262, 264, 266, 271, 278, 279 



Tricosphcerium sieboldii, 50, 51 



Tridacna fjigas, 692 



Trigger-hair See Cnidocil 

 nia, 678, 683, 692 



Trilobita, 589, 590, 591, 660 



Trimorphism, 130* 

 'i, 286 



Tristicothceta, 313 



TRITON RUBICUNDUS, 702 : Shell, 702, 

 703, 704 : External features of soft 

 parts, 704, 705 : Foot, 705, 706 : 

 Visceral spiral, 706 : Mantle, 706 : 

 Ctenidium, 706 : Osphradium, 706 : 

 Digestive system, 707, 708, 709 : 

 Vascular system, 709, 710, 711 : 

 Excretory system, 711 : Nervous 

 system, ^710, 711, 712 : Sensory 

 organs, 712 : Reproductive organs, 

 712, 713 : Systematic position, 715 



Tritonidce, 715*, 725 



Trivium, 370*, 407 



Trochal disc, 318* 



Trochelminthes, 316* : Appendix, 330 



Trocheta, 504 



Trochophore See Trochosphere 



Trochosphcera, 322, 325, 326, 328 



Trochosphaerida, 322* 



Trochosphere, 316, 430 



Trochus, 714, 727 



Trombidium fuliginosum, 649 



Tropho/oite, 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 



U LMARIDM. 176* 

 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 margaritifera, 662, 692 

 Unionid'jk, 678* 

 Unisexual, 40* 

 Urea, 37 

 Uric acid, 13, 37 

 Urinary bladder, 671* 

 Urinary organs, 37* 

 Urnatella, 347, 348 

 Urns, 487* 

 Urocoeles, 671* 

 Uropods, 530* 

 Uterine bell, 309 

 Uterus, 40* 



