36 



POST-TERTIARY LACUSTRINE SAND 



43. Pleurosigma rigidum. 



44. Synedra superba. 



45. „ acicularis. 



46. Gomphonema marinum. 



47. Achuanthes longipes. 



48. ,, brevipes. 



49. ,, subsessilis. 



50. Eliabdonema arcuatum. 



51. ,, minutiim. 



52. Zygoceros Siirirella.* 



53. Grammatophora marina. 



54. ,, serpentina. 



55. Ampbitetras antediluvianum. 



Total, 67 



56. Biddulpbia aurita. 



57. Melosira Borreri. 



58. ,, sulcata. 



59. Orthosira nummuloides. 



60. Podosira bormoides. 

 ,, maculata. 



Baciilaria paradoxa. 

 Dictyocba Speculum. 



„ gracilis. 



Fibula. 



,, trifenestra. 



Scbizonema Crux. 



61. 

 62. 

 63. 

 64. 

 65. 

 66. 

 67. 



species. 



II. Fresh-water Species, 

 including: such as occur in both fresh and brackish water : — 



Figured by Mr. Eoper in No. VIT. of tbe ' Journal.' 

 t Figured by Mr. Roper, loc. cit. 



X A new fresb-water species, first distinguished, I believe, by Professor 

 Walker Arnott. 



