CAMBRIAN GEOLOGY AND PALEONTOLOGY 



II 



No. 2.— MIDDLE CAMBRIAN MEROSTOMATA 



By CHARLES D. WALCOTT 



(With Six Plates) 



CONTENTS 



PAGE 



Introduction i8 



Cambrian Merostomata 19 



Classification 19 



Relations to pre-Cambrian Merostomes 21 



Sub-order Limulava, new sub-order 21 



Family Sidneyidae, new family 22 



Genus Sidneyia, new genus 22 



Sidneyia inexpectans, new species 24 



Cephalo-thorax 24 



Abdomen 24 



Ventral appendages 25 



Cephalo-thorax 25 



Abdominal 26 



Genus Amiella, new genus 27 



Aiiiiella ornata, new species 27 



Cephalo-thorax 27 



Abdomen 28 



Surface 28 



ILLUSTRATIONS 

 Plate page 



2. Sidneyia inexpectans 30 



3. Sidneyia inexpectans 32 



4. Sidneyia inexpectans 34 



5. Sidneyia inexpectans and Amiella ornata 36 



6. Neolenus serratus and Sidneyia inexpectans 38 



7. Sidneyia inexpectans and Beltina danai 40 



Smithsonian Miscellaneous Collections, Vol. 57, No. 2 



17 



