CONTENTS. Tu 



MOLLUSCA, OK SOFT-BODIED ANIMALS. 



FIBST GROUT THOSE DESTITXTTE OF A DISTINCT HEAD AcPphoIa. 



CLASS I.— TUNICATA. 



Pag* 



Meaning of the Term. — Paps. — Their Structure 163 



Parasite — Transparency Beauty of Colouring. — Pliospliorcsceuce 164 



Reproduction in the Salpae 1C5 



CLASS II BRACIIIOPODA. 



Meaning of the Term. — Peculiarity of Structure 165 



Depths at which they live 1G6 



CLASS IIL—LAMELLIBRAXCniATA. 



Jleaning of the Term 1G6 



Development of Ova. — Oyster: how supplied with Fooil 167 



Susceptibility to Light. — Growth 168 



Pearls — Pearl-divers and Fisheries 169 



Scallop. — ^lussei and its Byssus. — Silk of the Pinna 170 



Foot of the Cockle Use of the Limpet as Food 171 



Value of Oysters. — ^loUusca adapted to the character of the Coast 172 



Boring Species Teredo 173 



SECOND GROUP THOSE WITH A DISTINCT HEAD Encephola. 



CLASS I.— PTEROPODA. 



Meaning of the Term Clio borcalis: — Abundance of 17.5 



Its multitude of Suckers 176 



CLASS II.— GASTEROPODA. 



Meaning of the Term 17(i 



Variety and Be.iuty of some Marine Tribes (Nudihrunchiata) 177 



The Limpet: its Gills, Food, Tongue Chiton 178 



Sea-hare. — Planorbis 179 



Sense of feeling in the Slug. — Helix: number of Species 180 



U.ses as food 181 



Vermetu? — Habits of the "Whelk. — Purple dye of the Dog Whelk.. 182 



Tyrian Purple. — How procured 183 



CLASSIII.— CEPHALOPODA— CUTTLE-FISH. 



Structure. — Pearly Nautilus 184 



Ammonites — Commou Cuttle-fish. — LoUgopsis 185 



