418 



Great circle of, 44. 46. Orders 

 of, 49. Analogies of, 52. A single 

 grand genus, Testacea, imagined, 

 92. Families of exquisite spiral, 

 97. Series of fluviatile, 204. &c. 



Testacella, 327. 



Tethys, 24, 25. 



Textilia 312. 



Thallepus, 251. 359. T. ornatus, 

 251."n. 



Thallicera, 196. 339. T. avellana, 

 196. Analogies of, 210. 



Theliconus, 312. 



Theliderma, 268. 272. 377. T. 

 irrorata, nodosa, ' cylindrica, 

 pustulata, plicata, 272. T. cylin- 

 drica, 274. T. Peruviana, 276. 

 Analogies of the sectional types 

 of, 273. 



Thdidomus, 191. 194. Description 

 of, 228. 332. 353. 



TheJidonta, 193, 194. 



Thracia, 376. 



Tiara, typical form, 97. 319. 322. 

 Real type of Mitrina, 112. 129. 

 Analogies of, 130. 319. T. tere- 

 brans, 131. Sub-genera of, 320. 



Tiarella, 131. 319. 



Timorenia, 38. 



Tomella, 155. 314. 



Tornatella, 207. 343. 



Trachelipoda, of Lamarck, 24. 



Tremadotes of Rudolphi, 46. 



Trichopodus, 211. 



Tridacna, 257. 374. 



Trigonia, 383. 



Triphorus, 342. 



Triton, genus, 24, 25. The naked, 

 31. Swims in search of its prey, 

 34. Description of, 36. 50. 64. 

 297. T. clandestinum, 75. 



Tritonidea, 74. Remarks upon cha- 

 racters of, 74. 302. 



Trivea, 135. 325. 



Trochatella, 337. 



Trochella, 59.355. 



Trochia, 74. 302. 



Trochidae, are marine, 159. 211. 

 Genera of, 207. Habits of, 212. 

 Shells perlaceous, 212. Pyra- 

 midal, 212. Sub-families of, 213. 

 Analogies with those of Turbi- 

 das, 223. ; with the Achatinffi, 

 226. Family of, 347. 



Trochidon,351. 



Trochin^, described, 213. Oper- 

 culum horny, 216. Genera and 

 analogies of, 224. Sub-family, 

 349. 



Trochus, of Linneeus, 25. 350, 351. 

 Spiral, 47. Horny operculum of, 

 213. T. Niloticus, 216. T. zizy- 

 phinus, 218. T. merula, 219. 

 Strawberry, 220. Analogies of, 

 226. 



Tropics, the, Testacea of, 34. J 47. 



Truncatella, analogies of, 209. 343. 



Tubicanthus, 349. 



Tubulibranchia, comprehend Ver- 

 metus, Magilis, and SiUquaria, 

 25. Structure of, 36. 47. 54. 134. 



' 256. Characters of the tribe, 258. 

 Systematic arrangement of, 361. 



Tuliparia, 311. 



Turbidffi, family and circle of, 44. 

 341. The animals alone offer the 

 characters of, 160. Shells spiral, 

 with an operculum, and without 

 pearly lustre, 195. Typical ge- 

 nera of, 223. 



Turbinae, or winkles, 195. Analo- 

 gies of, 210. Characters of the 

 genera, 342. 



Turbinella, typical genus, 76. 94. 

 303. Fossil Clavalithes, 77. T. 

 Scolymus, 78. T. rapa, 78. 



TurbinellidEe, characteristics of 

 shell of, 75. 303. Sub-families of, 

 75. 243. Sub-typical group, spiny 

 and coronated, 115. Analogies 

 to the Cassidte, 89. Affinities to 

 the Muricidas, 95. 



Turbinellinas, 'smooth and heavy 

 shells of, 75. Analogies of Fusinae 

 and, 93. Arrangement, &c., 303. 



Turbo, of Linnasus, animal of, 25. 

 207. 345. Phytophagous and also 

 zoophagous, 47. Possesses a si- 

 phon, 160. 206. Figure of, 207. 

 T. sarmaticus, 213. .T. Nicoba- 

 ricus, 222. 



Turritella, resemblance with Tere- 

 bra, 74. 131. A typical genus, 

 206. Long-spired, 223. Charac- 

 ters of, 343. 



U. 



Umbrella, 62. 253. 361. 



Ungulina, 259.371. 



Unio circulus, 261. U. gigas, 263. 



275. U. margaritifera, 263. U. 

 cuneatus, 263. U. Esopus, 263. 

 271. U. mytiloides, 268. 270, 271. 

 292. U. torsus, 270. U. recta, 

 268. 272. U. cylindricus, 273. 



276. U. alata,279. U. nasutus, 

 279. U. truncatus, 270. U. no- 

 dosa, 270. U. obliqua, 270. U. 

 rugosus, 273. U. elongata, 275. 

 U. radiatus, 276. U. marginata, 

 278. U. fragilis, 279. U. Austra- 

 lis, 285. The typical, 264. Its 

 umbones, or bosses, 265. Distinct 

 types of, 268. 377. Analogies of 

 sub-genera of, 269. 274. Climate 

 inhabited by, 283. 



Unionidae, the, 257. 260. 264. 282. n. 

 Primary divisions of, 264. 377. 



