NO. 6 MIDDLE CAMBRIAN BRANCHIOPODA, ETC. I47 



PACE 



Genus Odaraia, new genus 187 



Odaraia alata, new species 188 



Genus Fieldia, new genus 188 



Fieldia lanceolata, new species (pi. 32) 188 



Genus Carnarvonia, new genus 189 



Cornarvonia venosa, new species (pi. 33) .'. . 189 



Sub-Class Trilobita 190 



Notes on appendages of Neolenus and Ptychoparia (pi. 24). ... 191, 192 



Descriptions of new genera and species 192 



Order (Undetermined) 192 



Family Marrellidae, new family 192 



Genus Marrella, new genus 192 



Marrella splendens, new species (pis. 25, 26) 193 



Family (Undetermined) 194 



Genus Nathorstia, new genus 194 



N athorstia transitans, new species (pi. 28) 194 



Appendages 195 



Dimensions 195 



Order Hypoparia Beecher 195 



Family (Undetermined) 195 



Genus Mollisonia, new genus 196 



Mollisonia symmetrica, new species (pi. 24) 196 



Mollisonia gracilis, new species (pi. 24) 197 



Mollisonia ? rara, new species (pi. 24) 198 



Genus Tontoia, new genus 198 



Tontoia kwaguntensis, new species (pi. 24) 199 



Sub-Class Merostomata 199 



Order Aglaspina, new order 199 



Family Aglaspidae Clarke 200 



Genus Molaria, new genus 200 



Mplaria spinifera, new species (pi. 29) 200 



Appendages 200 



Interior structure 201 



Dimensions 201 



Genus Hahelia, new genus 201 



Habelia optata, new species (pi. 29) 202 



Appendages 202 



Surface 202 



Dimensions 203 



Genus Emeraldclla, new genus 203 



Emeraldella brocki, new species (text fig. 8 and pi. 30) 203 



Appendages 203 



Alimentary canal 204 



Dimensions 204 



Emeraldella micrura, new species (text fig. 9) 205 



Order Limulava Walcott 205 



Family Sidneyidse Walcott 205 



Genus Sidneyia Walcott 205 



Sidneyia inexpectans Walcott (text fig. 10) 205 



