TABLE OF CONTENTS. 
Pack. 
CONOTRETA -. ______ 104 
Discinopsis - -- -- -- -- -- - 105 
SlNNARSSONIA ------ ------ 107 
Mesotreta. _____ 109 
SlPHONOTRETA - -- - - - - - - - - -110 
SCHIZAMBON.-.113 
Keyserlingia - - - - - - - - - - - -117 
Helmersenia ------------ 119 
Discina, Orbicula, Orbiculoidea, Schizotreta, Discinisca, Lindstroemella, 
(Ehlertella, Roemerella - - - - - - - - -120 
Trematis. 138 
SCH1ZOCRANIA ------------ 142 
Crania.- - - - - 146 
Craniella -. 153 
Cardinocrania.___ 154 
Pholidops.- - -155 
Note to page 128.160 
CONCLUSION - -. ------ 161 
SUPPLEMENT TO THE BRACHIOPODA INARTICULATA - - - - 171 
II. BRACHIOPODA ART1CULATA - 185 
Orthis.186 
Orthis - - - - - - - - - - - - -192 
Plectorthis.194 
Dinorthis ------ ------ - 195 
Plaesiomys . _____ 195 
Hebertella -. ------ 193 
Orthostrophia.199 
Platystrophia._ _____ 200 
Heterorthis - -- -- -- -- -- - 202 
Bilobites. ______ 204 
Dalmanella.-.205 
Rhipidomella. ______ _ 208 
Schizophoria - - - - . . - - - - - - - - 211 
Orthotichia - -- -- -- -- -- - 213 
Enteletes - - - - - - - - - - - 214 
List of G-enera and Species.220 
Supplementary Note on the Genus Orthis ------ 227 
Billingsella.230 
Proto rthis . 231 
Clitambonites.-.233 
P OLYTCECHIA.239 
SCENIDIUM.- 241 
Orthidium.-.244 
