iL : .rjilnnntnui nf 



THE figures on these Plates are little more than memorandum sketches, few or none of the details of 

 relief, sculpturing, striation, &c.., being given. They are, however, accurate as far as they go, being all, 

 except where otherwise stated, drawn by means of the camera-lucida, from living specimens. They may 

 serve, therefore, to identify the forms referred to in the descriptions. 



FIG. 1. Cosmarium depressum, H. 



2. Docidium undulatum, B. 



3. " minutum, Ralfs. 



4. nodosum, B. 



5. Mierasterias quadrats, B. 



6. " arcuata, B. 



7. " expansa, B. 



8. Docidium hirsutum, B. 



9. Triploceras verticillatum, B. 



10. " gracile, B. 



1 1 . Mierasterias ringens. 



12. " pinnatifida, Kg. 



13. " incisa, Kg. 



14. Spheerozosma serratum, B. 



PLATE I. 



FIG. 15. Didymocladon cerberus, B., side view. 

 1*3- cerberus, B., end view. 



17. longispinum, B. 



18. Staurastrum enonne, Rail's. 



19. Mierasterias oscitans, Ralfs, with abnormal 



teeth at a and b. 



20. Mierasterias denticulata, Ralfs. It has broad 



and slightly hirsute ends, which I have 

 not seen mentioned as occurring in the Brit- 

 ish specimens. 



21. Scale for all the figures in this Plate, being 



Truths of an inch, magnified equally with 

 the sketches. 



PLATE II. 



FIG. 1. Achnanthes lougipes ? Ag. Charleston. FIG. 



2. Amphiprora quadrifasciata, B. Tampa. 



3. " " seen obliquely. 



4. " " side view. 



5. " constricta, Ehr. Tampa. 



0. " " side view. Tampa. 



7. " " Ehr , large specimen. 

 Tampa. 



8, 9 Amphiprora alata, Ehr. St. Augustine. 



10. " " a contorted speci- 

 mrn, seen edgewise. 



11. Achnanthes, a single frustule, species un- 



determined. Volusia. 



12. Amphora libyca, Ehr. 



13. Pyxidicula compressa, B. St Augustine. 



14. " cross section of one valve. 



15. Amphiprora ornata, B. Withlacoochee R. 

 23. " a contorted specimen. 



16. pulchra, B , side view. 



18. " larger specimen, 



tVcuit view. Enterprise 



17. Ceratoneis closterium, Ehr. St. Augustine. 



19. Achnanthes ? arenicola, B. Tampa. 



20. Amphora amphiosys, B., ventral surface. 



St. Augustine. 



2 1 . oblique view. 



22. side view. 



24, 25. Campylodiscus argus, B. Hudson River. 



26. Cerataulus turgidus, Ehr. Hudson River, 



horns absent. 



27. Cerataulus turgidus, Ehr., with the horns. 



28. 38. Pinnularia permagna, B. Hudson River. 



29. Navicula cuspidata ? Ehr. Pilatka. 



30. Diatoma Ehrenbergii, Kg. Pilatka. 



32. Stauroneis maculata, B. Enterprise. 



33. Pinnularia Couperii, B. 



34. 35. Zygoceros (Denticella ?) mobilensis, B. 



36. Surirella circumsuta, B. 



37. Scale for all the figures on this Plate, being 



j-j^jths of an inch, magnified equally with 

 the drawings. 



