29. _Aldrovandia vesiculosa_ 138 30. _Aldrovandia_, its trap apparatus 139 31. Sea-cucumber (_Cucumaria_) 148 32. Metamorphosis of _Sitaris humeralis_, an oil-beetle 150 33. Cocoon of the Emperor Moth (_Saturnia carpini_) 158 34. Hermit-crab 163 35. _Hydra viridis_, the Green Freshwater Polyp 169 36. _Amœba viridis_ 170 37. Twig of an Imbauba-tree, showing hair cushions 172 38. A fragment of a Lichen 173 39. A fragment of a Silver Poplar root 176 40. _Potentilla verna_ 181 41. Flower of Meadow Sage 183 42. Alpine Lousewort (_Pedicularis asplenifolia_) 184 43. Flower of Birthwort (_Aristolochia clematitis_) 185 44. Alpine Butterwort (_Pinguicula alpina_) 185 45. _Daphne mezereum_ and _Daphne striata_ 187 46. Common Orchis (_Orchis mascula_) 188 47. Head of a Butterfly 190 48. Mouth-parts of the Cockroach 191 49. Head of the Bee 192 50. Flowers of the Willow 194 51. The Yucca-moth (_Pronuba yuccasella_) 201 52. The fertilization of the Yucca 202 53. Scent-scales of diurnal Butterflies 217 54. A portion of the upper surface of the wing of a male 'blue' (_Lycæna menalcas_) 218 55. _Zeuxidia wallacei_, male 218 56. _Leptodora hyalina_ 224 57. _Moina paradoxa_, male 225 58. _Moina paradoxa_, female 226 59. An Amœba: the process of division 253 60. _Stentor rœselii_, trumpet-animalcule 254 61. _Holophrya multifiliis_ 256 62. _Pandorina morum_ 257 63. _Volvox aureus_ 270 64. _Fucus platycarpus_, brown sea-wrack 272 65. Copulation in a Daphnid (Lyncæid) 276 66. Spermatozoa of various Daphnids 277 67. Spermatozoa of various animals 278 68. Diagram of a spermatozoon 279, 338