sor Owen's "Anatomy of Vertebrata"_) ... 73,
132

{xiv}
Cuttle-Fish ... 75, 141

Skeleton of Ichthyosaurus ... 78, 107, 132, 177

Cytheridea Torosa (_from Messrs. Brady and Robertson's paper in Ann. and
Mag. of Nat. Hist., 1870_) ... 79

A Polyzoon, with Bird's-head processes ... 80

Bird's-head processes greatly enlarged ... 81

Antechimis Minutissimus and Mus Delicatulus (_from Mr. Andrew Murray's
"Geographical Distribution of Mammals"_) ... 82

Outlines of Wings of Butterflies of Celebes compared with those of allied
species elsewhere ... 86

Great Shielded Grasshopper ... 89

The Six-shafted Bird of Paradise ... 90

The Long-tailed Bird of Paradise ... 91

The Red Bird of Paradise ... 92

Horned Flies ... 93

The Magnificent Bird of Paradise ... 93

_(The above seven figures are from Mr. A. Wallace's "Malay Archipelago"_)

Much enlarged horizontal Section of the Tooth of a Labyrinthodon (_from
Professor Owen's "Odontography"_) ... 104

Hand of the Potto (_from life_) ... 105

Skeleton of Plesiosaurus ... 106, 133

The Aye-Aye (_from Trans, of Zool. Soc._) ... 108

Dentition of Sabre-toothed Tiger (_from Professor Owen's "Odontography"_)
... 110

Trilobite ... 135, 171

Inner side of Lower Jaw of Pleurodont Lizard (_from Professor Owen's
"Odontography"_) ... 148

Solenodon (_from Berlin Trans._) ... 149

Tarsal Bones of Galago and Cheirogaleus (_from Proc. Zool. Soc._) ... 159

Squilla ... 160

Parts of the Skeleton of the Lobster ... 161 [Page xv]

Spine of Galago Allenii (_from Proc. Zool. Soc._) ... 162

Vertebrae of Axolotl (_from Proc. Zool. Soc._) ... 165

Annelid undergoing spontaneous fission ... 169, 211

Aard-Vark (_Orycteropus capensis_) ... 174

Pangolin (_Manis_) ... 175

Skeleton of Manus and Pes of a Tailed Batrachian (_from Professor
Gegenbaur's "Tarsus and Carpus"_) ... 178

Flexor Muscles of Hand of Nycticetus (_from Proc. Zool. Soc._) ... 180

The Fibres of Corti ... 279

{1}
* * * * *

THE GENESIS OF SPECIES.

CHAPTER I.

_INTRODUCTORY._

The problem of the genesis of species stated.--Nature of its probable
solution.--Importance of the question.--Position here
defended.--Statement of the DARWINIAN THEORY.--Its applicability to
details of geographical distribu