tV CONTENTS. 



Page 



Order II. — Astekoida, or Stak-siiaped Polypes 20 



Sea-pens 20 



Sea-fans; their Flexibility 21 



Different Structures of the Isis and of the Red Coral 22 



OuDEU III. — Hell^nthgida, ok those like the SL'N-FLOWEP. ... 22 



Sea-anemones 22 



Food, Longevity, Use as Barometers 23 



Power of enduring Injuries. — Coral-building Polypes 24 



Coral Eeefs. — Their Extent and Structure 25 



OrKER IV. ASCIDIOIDA, OR ASCIDIAX POLYPES 27 



Their Appearance and higher Organization 27 



Sea-mats — Their numerous Pol}T)es — Afiinity to the Mollusca 28 



CLASS IV.— RADIARIA, or RAYED AJN'IMALS. 



How characterised — their Division into two Orders 29 



Okdek I. — Acaleph^, or Sea-nettles 30 



Their gelatinous Structure 30 



Distribution — Diphya — Portuguese Man-of-war 31 



Velella — its mimic Fleets 32 



Bero'es, or Ciliogrades S3 



Their Movements, Habits, and Food 34 



Luminosity and Transparency 35 



Medusa:, or Pulmonigrades — Their Dimensions, Colours, Food 36 



Development 37 



Large proportion of Fluids in their Bodies 39 



Phosphorescence 40 



Numbers in the Arctic Sea 41 



Utility 42 



Order II. — Eciiinodermata, or Star-fishes 42 



Tiieir Integument, Transformations 43 



Ova and their Development — Variety of Form 44 



Stone-lilies, Crinoidea: — Their Beauty and former abundance 45 



Supposed to beextinct in Europe — Discovery of a living species 46 



Sand Star, 0;)/iiura-7-Structure — Diversity .,. 47 



"Five-fingers," Asteriadce — Their Suckers and their L'scs... 48 



Fragility oi Luidia 49 



Sea-Urchin, Echinus 50 



Mode of Progression — Structure of Shell — Respiration 52 



Jaws— Boring power of one Species 53 



Sea-cucumber, Holothuria — Sipuncular "Worms 55 



ARTICULATA, or AETICULATED ANIMALS. 



Characteristics of the Group 57 



lis Division into live Classes „ 58 



CLASS I.— ANNELLATA— LEECHES iVXD WORJIS. 



Medicinal Leeches — Supply of them CO 



Mouth, Stomach, Yoimg 61 



Kai'thworms — Tlxir Food, their Utility — Reproduction iu Worms... G2 



