954 DESCRIPTION OF THE ENGRAVr^TGS. 



surface; 50&52. s. v. 46. Cocconema cymbiforme (Ehr.), s. v. 47. Peridinium con- 

 strictum (Elii*.) : the median sulcus or constriction is well seen dividing the lorica into 

 two segments — patellce or valves, each of wliich is here again composed of several facettes. 

 A distinct nucleus (sexual gland, Ehr.) is shown. 48 r^ h. Cocconeis Americana (Elu*.): 

 48 a. s. V. ; 48 h. Several frustules adherent to a portion of Conferva. 54. Himantidium 

 Guianense (Ehr.), f. v. of a filament. 55,56,57. Colletonema Amphioxjs (Elu-.): 55. 

 B. v. of a single frustide ; 56. f. v. ; 57. A collection enclosed in their mucous investment, 

 seen in difi'erent positions. 58. Sphserozosma? . . . (Brightwell): tliis production was 

 found by Mr. Brightwell (see ' Famia Infusoria of Norfolk'). We cannot perceive any 

 affinity between his drawing and the members of the genus Sphcerozosma, to which he has 

 surmised it might belong. 59. Ceratoneis Closterium (Ehr.), s. v. 60, 61. Pleurosigma 

 Fasciola (Ehr.). 62, 63. Dictyocha Speculum (Elu\): 62. Viewed in front; 63. Viewed 

 sideways. 64. Difllugia acanthophora (Ehr.) : its surface illustrates what is termed an 

 imbricate disposition of the scale-like markings ; a navicular body is represented in its 

 interior, as seen tln-ough its transparent lorica. 65, 66. Asplanchna Brightwellii (Bright- 

 well). These two figures are from Mr. Brightwell's book : 65 is there described as " a 

 young specimen (female), just emerged, in which the red eye and germs of other organs 

 are seen ; " in 66 " may be seen the oesophagus leading to the stomach, and above the 

 stomach two small bodies (either salivary or hepatic glands), and mider it the opaque 

 ovisac." 67, 68, 69. Zoothamniiun Ai'buscula (Brightwell) : these tln*ee figures from 

 Mr. Brightwell illustrate the curious cycle in development referred to in the text. 70. 

 Vaginicola . . . ? (Brightwell) : apparently a Vaginicola imdergoing spontaneous fission. 

 71. Mesocena heptagona (Ehr.). 72. Navicula cardinalis (Ehr.), s. v. 73. Stauroneis 

 Isostauron (Elu-.), s.v. 



PLATE XIII. (Diatoms). 



Figure 1. Amphipleura pellucida. 2. A. rigida. 3. Surirella constricta. 4. Den- 

 ticula elegans. 5, 6, 7. Amphiprora alata. 8. Epithemia alpestris. 9. Ceratoneis 

 spiralis. 10. Cocconema gibbum. 11. Gomphonema cm'vatum. 12. Epithemia Por- 

 cellus. 13. (left) Podosphenia hyalina ; (right) P. cuneata. 14. P. Ehrenbergii. 

 15. Ehipidophora tenella. 16. Licmophora divisa. 17. Ehipidophora Nubecula. 

 18. Epithemia Musculus. 19. Ehipidophora Meneghiniana. 20. Synedra fulgens. 

 21. Meridion circulare, var. 22. Grammatophora hamulifera. 23. Gomphonema 

 acuminatum. 24, 25. Odontidium hyemale. 26. Tabellaria ventricosa. 27. Ehab- 

 donema Adriaticum. 28.' Pododiscus Jamaicensis. 29. Tabellaria flocculosa. 30, 31, 

 32, 32 a. Biddulphia obtusa. 33. Pyxidicula Adriatica. 



PLATE XIV. (Diatoms). 



Figures 1 to 12. Fragilaria capucina. 13. Himantidium Soleirolii. 14. Cym- 

 bosira Agardhii. 15. Achnantliidium microcephalum. 16. A. delicatulum. 17. Cyclo- 

 tella Scotica. 13, 19, 20. Cymbella gastroides. 21, Ehaphoneis Amphiceros. 22. 

 Encyonema prostratum. 23. Hyalosira rectangula. 24-28. Cymbella Helvetica. 29. 

 Hyalosira obtusangula. 30. Sphenella angustata. 31. S. obtusata. 32, 33. Diadesmis 

 confervacea. 34, 35 a, h. Berkeleya Adriatica. 36. Gomphonema coronatum. 37, 

 38 «, h, c. Homoeocladia pumila. 39-42. Micromega pallidum. 43, 44. M. bomby- 

 cinum. 45, 46. Homoeocladia moniliformis. 47-49. H. Martiana. 



PLATE XV. (Diatoms). 



Figures 1, 2. Cyclotella atmospherica (Elir.). 3. C. Atlantica (Ehr.). 4. C. Sinensis 

 (Ehr.). 5. Stawosira construens (Ehr.). 6, 7, 8, 9. Epithemia longicornis (Ehr.). 10. 

 Goniothecium crenatiun (Ehr.). 11. Epithemia Argus (Ehr.). 12. Navicula didyma (Ehr.). 

 13. Desmogonimu Guianense (Ehr.). 15. Naviculatajniata (Eln-.). 16,17. Himantidimn 

 monodon (Ehr.) : 16. Two frustules conjoined in front view ; 17. s. v. 18, 19, 20, 21, 

 Arachnoidiscus ornatus (Shadbolt) : 18. External membi'ane, as seen when detached from 

 the inner framework, or when viewed from the outside of the shell as an opaque object ; 

 19. The inner framework is exliibited on a black disc as an opaque object ; 20. The mem- 

 brane and framework united, as seen by transmitted light, x200; 21. The same, more 

 amphfied, XoOO. 22,23. Campylodiscus parvulus (Smith) : 22. s.v.; 23. Partial f. v. 

 24, 25. Grammonema Jm'gensii (Ealfs) : 24. Front and s.v. of a single frustule; 25. A 

 filament. 26, 27. Melosira Niigeli : a series of figures to illustrate the distribution of the 

 chlorophyll (endochrome), and the presence of a nucleus : 26 a. viewed from the base ; 



