s''- 





CONTENTS. 



Introduction i 



Branch I. — Protozoa 1 



Class I. — JIoneka 2 



Class II. — PaiizopoDA 4 



Class III. — Gregaeinida 2.3 



Class IV. — Infusoria 26 



Branch II. — Poriferata 49 



Class I. — Cai.cispongi^ 61 



Class II. — CABNEOspoNGiiE 63 



Branch III. — Ccelentekata 72 



Class I. — Hydrozoa 73 



Order I. — Hydroidea 73 



Order II. — Discophora 89 



Class II. — Siphonophora 97 



Order I. — Physophor^ 98 



Order II. — Pneu.matopuor.e 104 



Order III. — Dipuy-.e 105 



Order IV. — Discoide^ 107 



Class III. — Ctenophora ' . . . .108 



Class IV. — Actinozoa 112 



Order I. — Zoantiiaria 116 



Oudeu II. — Halcyonoida 121 



Branch IV. — Echinodermata 135 



Class I. — Crinoidea 139 



Op>der I. — Blastoidea 1.39 



Order II. — Cystidea . 139 



Order III. — Brachiata 140 



Class II. — Stellep.ida 147 



Order I. — Opiiiuroidea 147 



Order II. — Asteroidea 152 



Class III. — Echinoidea 161 



Order I. — Desmosticha 164 



Order II. — Clypeastrid.e 170 



Order III. — Petalosticha 172 



Class IV. — Holothuroidea 176 



Order I. — Elasipoda 179 



Order II. — Apoda 179 



Order III. — Pedata 180 



Order IV. — Diplostomidea 183 



