Metamorphoses and Homologies 102 Larva, First Stage 103 Larva, Second Stage 109 Larva in the Last or Pupal Stage 110 Act of Metamorphosis 126 On the Homologies of the Carapace and Shelly Valves 131 Cementing Apparatus 133 Affinities, Classification, Variation 152 Rate of Growth, Exuviation, Powers of Repairing Injuries 156 Geographical Range and Habits 159 Geological History 172 Sub-Family Balaninæ 175 1. Genus Balanus 177 Sections of the Genus 193 Section A 194 1. Balanus tintinnabulum 194 Var. communis, vesiculosus, validus, zebra, crispatus, spinosus, coccopoma, concinnus, intermedius, occator, d'Orbignii Varieties 201 2. Balanus tulipiformis 204 3. Balanus psittacus 206 4. Balanus Capensis 209 5. Balanus Nigrescens 210 6. Balanus decorus 212 7. Balanus vinaceus 213 8. Balanus Ajax 214 Section B 216 9. Balanus stultus 216 10. Balanus calceolus 218 11. Balanus galeatus 220 12. Balanus cymbiformis 221 13. Balanus navicula 221 Section C 223 14. Balanus trigonus 223 15. Balanus spongicola 225 16. Balanus lævis 227 Var. nitidus, Coquimbensis 17. Balanus perforatus 231 Var. angustus, Cranchii, fistulosus, mirabilis 18. Balanus concavus 235 19. Balanus amphitrite 240 Var. communis, venustus, pallidus, niveus, modestus,