CONTENTS EDITORIAL NOTE. VOLCANIC ISLANDS. DETAILED TABLE OF CONTENTS GEOLOGICAL OBSERVATIONS ON VOLCANIC ISLANDS. CHAPTER I.—ST. JAGO, IN THE CAPE DE VERDE ARCHIPELAGO. CHAPTER II.—FERNANDO NORONHA; TERCEIRA; TAHITI, ETC. CHAPTER III.—ASCENSION. CHAPTER IV.—ST. HELENA. CHAPTER V.—GALAPAGOS ARCHIPELAGO. CHAPTER VI.—TRACHYTE AND BASALT.—DISTRIBUTION OF VOLCANIC ISLES. CHAPTER VII.—AUSTRALIA; NEW ZEALAND; CAPE OF GOOD HOPE. INDEX TO VOLCANIC ISLANDS. A MONOGRAPH ON THE SUB-CLASS CIRRIPEDIA (Vol. 1 of 2) The Lepadidae; or, Pedunculated Cirripedes By Charles Darwin CONTENTS List of Species Lepas 67 1. Lepas anatifera 73 2. Lepas Hillii 77 3. Lepas anserifera 81 4. Lepas pectinata 86 5. Lepas australis 89 6. Lepas fascicularis 92 Pæcilasma 99 1. Pæcilasma Kæmpferi 102 2. Pæcilasma aurantia 105 3. Pæcilasma crassa 107 4. Pæcilasma fissa 109 5. Pæcilasma eburnea 112 Dichelaspis 115 1. Dichelaspis Warwickii 120 2. Dichelaspis Grayii 123 3. Dichelaspis pellucida 125 4. Dichelaspis Lowei 128 5. Dichelaspis orthogonia 130 Oxynaspis 133 1. Oxynaspis celata 134 Conchoderma 136 1. Conchoderma aurita 141 2. Conchoderma virgata 146 C. virgata, var. chelonophilus 151 C. virgata, var. Olfersii 152 3. Conchoderma Hunteri 153 Alepas 156 1. Alepas minuta 160 2. Alepas parasita 163 3. Alepas cornuta 165 4. Alepas tubulosa 169 Anelasma 169 1. Anelasma squalicola 170 Ibla 180 1. Ibla Cumingii 183 2. Ibla quadrivalvis 203 Scalpellum 215 Sub-Carinâ Nullâ 222 1. Scalpellum vulgare 222 2. Scalpellum ornatum 244 3. Scalpellum rutilum 253 Sub-Carinâ Presente 259 4. Scalpellum rostratum 259 5. Scalpellum Peronii 264 6. Scalpellum villosum 274 Pollicipes 293 1. Pollicipes cornucopia 298 2. Pollicipes elegans 304 3. Pollicipes polymerus 307 4. Pollicipes mitella 316 5. Pollicipes spinosus 324 6. Pollicipes sertus 327 Lithotrya 331 1. Lithotrya dorsalis 351 2. Lithotrya cauta 356 3. Lithotrya nicobarica 359 4. Lithotrya rhodiopus 363 5. Lithotrya truncata 366 6. Lithotrya Valentiana 371