VARIATION OF SKULLS OF URSUS LABIATUS
16. " VARIATION OF SKULLS OF SUS CRISTATUS
17. PRIMULA VERIS (Cowslip). From Darwin's _Forms of Flowers_
18. GAZELLA SOEMMERRINGI (to show recognition marks)
19. RECOGNITION MARKS OF AFRICAN PLOVERS
(from Seebohm's _Charadriadae_)
20. RECOGNITION OF OEDICNEMUS VERMICULATUS AND OE. SENEGALENSIS
(from Seebohm's _Charadriadae_)
21. RECOGNITION OF CURSORIUS CHALCOPTERUS AND C. GALLICUS
(from Seebohm's _Charadriadae_)
22. RECOGNITION OF SCOLOPAX MEGALA AND S. STENURA
(from Seebohm's _Charadriadae_)
23. METHONA PSIDII AND LEPTALIS ORISE
24. OPTHALMIS LINCEA AND ARTAXA SIMULANS
(from the Official _Narrative of the Voyage of the Challenger_)
25. WINGS OF ITUNA ILIONE AND THYRIDIA MEGISTO
(from _Proceedings of the Entomological Society_)
26. MYGNIMIA AVICULUS AND COLOBORHOMBUS FASCIATIPENNIS
27. MIMICKING INSECTS FROM THE PHILIPPINES
(from Semper's _Animal Life_)
28. MALVA SYLVESTRIS AND M. ROTUNDIFOLIA
(from Lubbock's _British Wild Flowers in Relation to Insects_)
29. LYTHRUM SALICARIA, THREE FORMS OF
(from Lubbock's _British Wild Flowers in Relation to Insects_)
30. ORCHIS PYRAMIDALIS (from Darwin's _Fertilisation of Orchids_)
31. HUMMING-BIRD FERTILISING MARCGRAVIA NEPENTHOIDES
32. DIAGRAM OF MEAN HEIGHT OF LAND AND DEPTH OF OCEANS
33. GEOLOGICAL DEVELOPMENT OF THE HORSE TRIBE
(from Huxley's _American Addresses_)
34. DIAGRAM ILLUSTRATING THE GEOLOGICAL DISTRIBUTION OF PLANTS
(from Ward's _Sketch of Palaeobotany_)
35. TRANSFORMATION OF ARTEMIA SALINA TO A. MILHAUSENII
(from Semper's _Animal Life_)
36. BRANCHIPUS STAGNALIS AND ARTEMIA SALINA
(from Semper's _Animal Life_)
37. CHIMPANZEE (TROGLODYTES NIGER)

CHAPTER I

WHAT ARE "SPECIES," AND WHAT IS MEANT BY THEIR "ORIGIN"

Definition of species--Special creation--The early
Transmutationists--Scientific opinion before Darwin--The problem
before Darwin--The change of opinion effected by Darwin--The
Darwinian theory--Proposed mode of treatment of the subject.

The title of Mr. Darwin's great work is--_On the Origin of Species by
means of Natural Selection and the Preservation of Favoured Races in the
Struggle for Life_. In order to appreciate fully the aim and object of
this