694 DE8CEIPTI0N OF ENGEAVINGS. 



PLATE XV {continued.) 



Figs. 11. Surirella flexuosa (Ehr.) — A side view. 



12, 13, 22, and 23. Surirella Campylodiscus (Ehr )— Figs. 12 and 22, side 



views ; fig. 23, seen on face ; fig. 13, viewed lying on one end. 

 15 and 31. Pinnularia viridis (Ehr.) — Fig. 15, ventral surface; fig. 31, viewed 



laterally. 

 16. Stauroneis dilatata (Ehr.) — A dorsal or ventral view. 

 17 and 18. Stauroneis phoenicenteron (Ehr). — Fig. 17, lateral surface; fig. 18, 



ventral aspect. 

 19 and 20. Surirella Craticula (Ehr.) — Fig. 19, lateral; fig. 20, ventral surface. 

 21. Pinnularia Tabellaria (Ehr.) — Ventral aspect. 

 24 and 25. Eunotia Librile (Ehr.) — Fig. 24, ventral surface; fig. 26, front 



view (lateral surface.) 



26. Amphora gracilis (Ehr.) — Ventral aspect. 



27. Eunotia gihba (Ehr.) — Ventral surface. 



28 and 53. Gomphonema apiculatum (Ehr.) — Fig. 28, a front view of two con- 

 catenated frustules ; fig. 53, ventral surface. 

 29. Eunotia Monodon (Ehr.) — A front view. 



32. Ndvicula affinis (Ehr.) — Ventral surface. 



33. Pinnularia Chilensis (Ehr.) — ^ Ventral surface. 



34 and 36. SjTiedra Gallionii (Ehr.) — Fig. 34, front view of four conjoined; 



fig. 36, a lateral view. 

 35. Gomphonema Vibrio (Ehr.) — Dorsal or ventral aspect. This aspect is, 



strictly speaking, that of the junction-surfaces. 



37. Amphora Navicularis (Ehr.) — Ventral surface. 



38. Amphora Lybica (Ehr.) — Venti-al surface. 



39. Eunotia quinaria (Ehr.) — Viewed laterally, so that the five dentations 



(teeth) on the dorsum are exhibited. 



40. Tabellaria laevis (Ehr.) — A front view of four conjoined. 

 ■ 41. Cocconeis Finnica (Ehr.)— Ventral surface. 



42. Cocconeis Oceanica (Ehr.) — Dorsal surface. 



43. Pinnularia Esox (Ehr.) — Ventral aspect. 



44. Synedra Valens (Ehr.) — Front view. 



45. 49, 50, 51 and 52. Himantidium Papilio (Ehr.)— Figs. 45 and -51. several 



conjoined segments viewed from above ; fig. 49, a single frustule seen 

 on ventral surface ; figs. 50 and 52, end view, or a single frustule 

 in section. 



46. Coccouema Cymbiforme (Ehr.) — Ventral surface. 



47. Peridinium constrictum (Ehr.) — The median sulcus or constriction is well 



seen dividing the lorica into two segments. — patella; or valves, each of 

 which is here again composed of several facettes. A distinct nucleus 

 (sexual gland, Ehr.) is shown. 

 48a. and 6. Cocconeis Mexicana (Ehr) — Fig. 48 a, a single frustule seen on 

 ventral surface ; fig. 48 b, several frustules adherent to a portion of 

 Conferva. 



54. Himantidium Guianense (Ehr.) — Front view of several concatenated 



frustules. 



55, 56 and 57. Naunema Amphioxys (Ehr.)— Fig. 55, a single frustule on 



dorsum ; fig. 56, on its side ; fig. 57, a collection enclosed in their 

 mucous investment, seen in different positions. 



58. Spherozosma ? ... (Brightwell.) — This production was found by Mr. 



Erightwell (see Fauna Infusoria of Norfolk.) We cannot perceive any 

 affinity lictwcen his drawing and the members of the genus Sphoerozosma , 

 to whicli he has surmised itmiglit belong. 



59. Ccratoucis Closterium (Ehr.) — Dorsal or ventral surface. 



