PLATE XLIII 



PAGE 



Figs. 1-5. LEPEBDITIA FABULITES (Conrad) 364 



1. Cast of interior of right (larger) valve showing impressions of 



papillae along ventral margin. X 2. 



2, 3. Ventral and dorsal views of a complete carapace. X 2. 



4. Left valve of the same. X 2. 



5. Posterior view. X 2. 



Ordovician (Mohawkian), Black River (Platteville) Is., 

 Minneapolis, Minnesota. 



Figs. 6-9. MACBONOTEULA ULBICHI Ruedemann 368 



6. 7. Ventral and lateral views of a large valve. X 14. 



8, 9. Similar views of another specimen showing the specific char- 

 acters well developed. X 14. 



Ordovician (Mohawkian), Rysedorph conglomerate, Ryse- 

 dorph Hill, Rensselaer County, New York. 



Figs. 10-12. LEPEBDITELLA TUMIDA (Ulrich) 366 



10. Right valve. X 10. 



11, 12. Dorsal and posterior views of same in outline. X 10. 



Ordovician (Mohawkian), Black River (Lowville) Is., High 

 Bridge, Kentucky. 



Figs. 13-15. DREPANELLA MACBA Ulrich 367 



13. Left valve. X 20. 



14, 15. Sectional views of same between points marked c and b. 



Ordovician (Mohawkian), Stones River (Lebanon) Is., La- 

 vergne, Tennessee. 



Figs. 16, 17. OMOSPIBA ALEXANDRA (Billings) 308 



16. Cast of the interior. 



Ordovician (Mohawkian), Black River (Platteville) Is., 

 Dixon, Illinois. 



17. An imperfect, silicified shell. 



Black River (Lowville) Is., Mercer County, Kentucky. 



Figs. 18-21. PTEBYGOMETBOPUS CALLICEPHAI.US (Hall) 360 



18. A nearly complete pygidium of large size. 



19. A small complete pygidium. 



20. An incomplete head. 



Ordovician (Mohawkian), Trenton portion Jacksonburg Is., 

 Jacksonburg, New Jersey. 



21. Complete individual. 



Ordovician (Mohawkian), Trenton Is. of Canada. 



Figs. 22, 23. CERAUBUS PLEUREXANTHEMUS Green 358 



22. An incomplete cranidium. 



Ordovician (Mohawkian), Trenton portion of Jacksonburg Is., 

 Jacksonburg, New Jersey. 



23. General aspect of species of this type. The original of this figure 



has since been referred to a new species, C. dentatus Raymond 

 and Barton. 



Trenton. Is., of Canada. 



Figs. 1-5, 10-15 are after Ulrich ; 6-9 after Ruedemann ; 16, 17, 

 21, 23 after Billings; 18-20, 22 after Weller. 



393 



