NO. 6 MIDDLE CAMBRIAN BRANCHIOPODA, ETC. 



PAGE 



Merostomata, subclass 199 



Classification of 155 



Bidentia difficilis nearer to. than to Branchiopoda 174 



descent of 160-161 



foreshadowed by Burgess shale fauna 165 



line of descent 164 



origin of 165 



relations of, to Branchiopoda, Leptostraca, Merostomata, and Trilo- 



bita (63 



representatives of 155 



segmentation, table of 158 



mentioned 148, 153, 155 



Merostomes, named and characterized 158 



Metastoma or labium 158 



Microdiscus, compared with Mollisonia 196 



mentioned 149, 151 



inicntra, see Emeraldella. 



Middle Cambrian, Hynienocaris distributed in 155 



Middle Cambrian Branchiopoda, Naraoia compacta an addition to 176 



Middle Cambrian Burgess shale, representatives of Merostomata in 155 



Middle Cambrian Crustacean fauna, discussion of origin 160-164 



Miskoia preciosa, stratigraphic position and association 152 



Molar, mountain peak, Alberta, Canada 200 



Molaria, new genus, discussed 200 



between Branchiopoda and Merostomata 163 



characterized 158 



classification of 155 



epipodite and protopodite of 159 



representing Merostomata 155 



Molaria spinifera, new species 200, pi. 29, figs. 1-5 



appendages of 200 



compared with Nalhorstia transit ans 195 



related to Emeraldella brocki 201 



relation to Nathorstia transitans 191 



stratigraphic position and association 152 



Mollison, mountain in British Columbia, Canada 196 



Mollisonia, new genus described and discussed 196 



classification of 154 



compared with Agnostus and Microdiscus 196 



tentatively referred to Microdiscidse Coquin 195 



thorax of, recalls BohcmiUa stupenda Barrande 196 



mentioned 155 



Mollisonia gracilis, new species 197, pi. 24, fig. 5 



compared with Mollisonia symmetrica 198 



stratigraphic position and association 15-2 



Mollisonia ? rara, new species 198, pi. 24, figs. 6 and 7 



stratigraphic position and association 152 



