iV CONTENTS. 



Page 



ORDER II. ASTEROIDS, or. STAR -SHAPED POLYPES , 20 



Sea-pens 20 



Sea-fans; their Flexibility 21 



Different Structures of the Isis and of the Red Coral 22 



OKOER III. HELIANTHOIDA, OR THOSE LIKE THE SUN-FLOWER... 22 



Sea-anemones 22 



Food, Longevity, Use as Barometers 23 



Power of enduring Inj uries. Coral-building Polypes 24 



Coral Reefs. Their Extent and Structure .'. 25 



OllI'EU IV. ASCIDIOIDA, OR AsCIDIAN POLYPES 27 



Their Appearance and higher Organization 27 



Sea-mats Their numerous Polypes Affinity to the Mollusca 28 



CLASS IV.RADIARIA, OR RAYED ANIMALS. 



How characterised their Division into two Orders 29 



ORDER I. ACALEPH^E, OR SEA-NETTLES 30 



Their gelatinous Structure 30 



Distribution Diphya Portuguese Man-of-war 31 



Velella its mimic Fleets 32 



Berocs, or Ciliogrades 33 



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. ECHINODERMATA, OR STAR-FISHES 42 



Their Integument, Transformations 43 



Ova and their Development Variety of Form 44 



Stone-lilies, Crinoidecc Their Beauty and former abundance 45 



Supposed to be extinct in Europe Discovery of aliving species 46 



Sand Star, Ophiura Structure Diversity 47 



"Five-fingers," Asteriadce Their Suckers and their Uses... 48 



Fragility of 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 ARTICULATED ANIMALS. 



Characteristics of the Group 57 



Its Division, into five Classes 58 



CLASS L ANNELLATA LEECHES AND WORMS. 



Medicinal Leeches Supply of them CO 



Moutii, Stomach, Young 61 



Earthworms Their Food, their Utilitv Reproduction in \Yupns... G2 



