40. Balanus flosculus 290 Var. sordidus 41. Balanus bisulcatus 293 Var. plicatus 42. Balanus dolosus 295 43. Balanus unguiformis 296 Var. erisma 44. Balanus varians 298 45. Balanus inclusus 299 2. Sub-Genus Acasta 302 1. Acasta spongites 308 2. Acasta sulcata 310 3. Acasta cyathus 312 4. Acasta undulata 313 5. Acasta glans 314 6. Acasta lævigata 315 7. Acasta fenestrata 316 8. Acasta purpurata 318 9. Acasta sporillus 319 3. Genus Tetraclita 321 1. Tetraclita porosa 329 Var. communis, nigrescens, viridis, rubescens, elegans, communis (young), patellaris 2. Tetraclita serrata 334 3. Tetraclita rosea 335 4. Tetraclita purpurascens 337 5. Tetraclita costata 339 6. Tetraclita vitiata 340 7. Tetraclita corulescens 342 8. Tetraclita radiata 343 4. Genus Elminius 345 1. Elminius Kingii 348 2. Elminius modestus 350 3. Elminius plicatus 351 4. Elminius simplex 353 5. Genus Pyrgoma 355 1. Pyrgoma anglicum 360 2. Pyrgoma Stokesii 361 3. Pyrgoma cancellatum 362 4. Pyrgoma conjugatum 364 5. Pyrgoma grande 365 6. Pyrgoma milleporæ 367 7. Pyrgoma dentatum 369 8. Pyrgoma crenatum 370 9. Pyrgoma monticulariæ 372 Species dubiæ 374 6. Sub-Genus Creusia 375 1. Creusia spinulosa 376 Varieties with the Scuta and Terga calcified together 380 7. Genus Chelonobia 382 1. Chelonobia testudinaria 392 2. Chelonobia caretta 394 3. Chelonobia patula 396 Second Section of the Sub-Family of Balaninæ 397 8. Genus Coronula 397 1. Coronula balænaris 415 2. Coronula diadema 417 3. Coronula reginæ 419 4. Coronula barbara 421 Species Dubiæ 423 9. Genus Platylepas 424 1. Platylepas bissexlobata 428 2. Platylepas decorata 429 Species Dubiæ 430 10. Genus Tubicinella 430 1. Tubicinella trachealis 431 11. Genus Xenobalanus 438 1. Xenobalanus globicipitis 440 Sub-Family Chthamalinæ 446 12. Genus Chthamalus 447 1. Chthamalus stellatus 455 Var. communis, fragilis, depressus 2. Chthamalus antennatus 460 3. Chthamalus cirratus 461 4. Chthamalus fissus 462 5. Chthamalus dentatus 463 6. Chthamalus Hembeli 465 7. Chthamalus intertextus 467 8. Chthamalus scabrosus 468 13. Nov. Genus Chamæsipho 470 1. Chamæsipho columna 470 2. Chamæsipho scutelliformis 472 14. Nov. Genus Pachylasma 475 1. Pachylasma giganteum 477 2. Pachylasma aurantiacum 480 15. Genus Octomeris 482 1. Octomeris angulosa 483 2. Octomeris brunnea 484 16. Genus Catophragmus 485 1. Catophragmus polymerus 487 2. Catophragmus imbricatus 490 Remarks on Bronn's List of Fossil Balaninæ and Chthamalinæ 492 Family Verrucidæ 495 Genus Verruca 496 Powers of Excavation 512 1. Verruca Strömia 518 2. Verruca lævigata 520 3. Verruca Spengleri 521 4. Verruca nexa 522 5. Verruca prisca 525 Family Lepadidæ 526 Genus Alcippe 529 Alcippe lampas 530 Female 530 Male 555 Order II.-Abdominalia 563 Cryptophialus minutus 566 Female 566 Male 584 Order III.-Apoda 587 Proteolepas bivincta 589 Synopsis et Index Systematicus 606