CONTENTS. XV 



PAGE 



System of the Protozoa — Ledenf eld's Investigations on a Nervous 

 System in the Porifera — The Nervous System of the Cclcnterata : 

 Researches of Kleinenberg, Romanes, Haeckel, Hertwig, and 

 others ; Experiments of Romanes on the Nervous System of the 

 Medusa: Eimer's Investigations on Ctenophora — The Nervous 

 System of the Echinodermata : Researches of Romanes, Ewart, 

 Fredericq, Prouho, and Hamann ; Internal and External Nerve- 

 plexuses of Echinus — Nervous Systems of the Tricltoscolices, Anne- 

 lida, Xematoscolices, CJuetognatha, Prototracheata, and Myriapoda — 

 The Nervous Systems of the Inseda : The Cerebral Ganglion or 

 Brain — The Nervous Systems of the Arachnida and Crustacea : 

 Investigations of Sars, Fredericq, Vandevelde, and Griffiths — The 

 Nervous Systems of the Polyzoa, Brachiopoda, 31ollusca, and 

 Tunicata, &c. ... . , , . . 293 



CHAPTER XI. 



The Organs of Special Sense, &c., in the Invertebrata : Tactile Sensi- 

 bility and Sight in the Protozoa and Porifera — The Cidenterata : 

 Rudimentary Eyes and Olfactory Organs in the 3Iedusce — The 

 Echinodermata : Tactile Sensibility ; Sense of Smell : Experiments 

 of Griffiths; Sense of Hearing ; Eyes: Researches of Romanes 

 and Ewart — The Sense-organs in the Trichoscolices, Annelida, 

 Nematoscolices, Chwtognatha, and Myriap)odu — Sense-organs in the 

 Insecta : Tactile Organs ; The Senses of Taste, Smell, and Hearing ; 

 Simple and Compound Eyes of Insects, Mosaic Vision ; The 

 " Voices " of Insects— Sense-organs in the Crustacea : Blind Cave- 

 crabs, Cirripedia, Crayfishes, &c. — Sense-organs in the Mollusca : 

 Organs of Touch, Taste, Smell, Hearing, and Sight ; The Cepha- 

 lopod Eye — Intelligence or Reason in certain Invertebrates, cScc. . 345 



CHAPTER XII. 



Movements and Locomotion in the Invertehrata : In the Protozoa: 

 Pseudopodia, Flagella, and Cilia as locomotive organs ; Researches 

 of Dallinger and Drysdale ; The Muscular Fibre in the Peduncle 

 of Vorticella — Movements in the Porifera — Locomotion, &c. , in the 

 Ccclenterata : Researches of Romanes— Locomotion, &c., in the 

 Trichoscolices, Annelida, Nematoscolices, and Myriapoda ; Loco- 



