P. T. CLEVE ON SOME FOSSIL MARINE DIATOMS. 177 



fragments frequently occur ; my specimen is imperfect (about two- 

 thirds of a valve.) This form has also some resemblance to A. 

 superb us, Kitton. 



Cosmiodiscus, Barbadensis, Grev., (?) var. I have seen two or 

 three valves of what I take to be Greville's species. This form is 

 very common in a Tegel from Struhar, Hungary. 



Arachnoidiscus Ehrenbergii. One specimen. 



AsteroJampra Marylandica. One specimen. 



Navicula aspera, var. intermedia. If the fact of the lines of 

 striae on one side of the median line being shorter than on the 

 other is of any generic value, the above-named diatom belongs to 

 the genus Alloioneis ; but I have found forms with the pseudo 

 stauros and the lines of striae equal (A r . aspera type); without the 

 stauros and the lines of stria? also equal; with the stria? unequal 

 (Alloioneis) ; with stria* nearly touching the median line, and an 

 inconspicuous blank space round the central nodule. All these 

 forms have the characteristic stria? of the type form, and gradually 

 merge into each other. 



DESCRIPTION OF PLATES. 



Plate XII. 



Fig. 1. Navicula gemmatula, var ? 4 £°. 



" 2, Campylodiscus obsoletus, CI., n.sp., a, 2 f°, b. c. 10 T °. 



3. Syringidium, sp., 4 ^°. 



4. Triceratium turgidum, CI., n.sp., 2 ^°. 



5. ,, Stokesianum, a. b., 2 ^°. 



6. ,, trisulcum, var. minor, CI., 4 y°. 



7. „ tesselatum, 4 ^°. 



8. Aulacodiscus Gruuowii, CI., n.sp., 2 f°. 



a 

 (( 



Plate XIII. 



Fig. 9. Anliscus pnlvinatus, CI., n.sp., 4 -p 8 . 

 " 10. Actinoptychus vulgaris, var. 1 °f° . 

 "11. „ „ var. Virginica, 10 f °. 



"12. „ Boliviensis, var. Pfitzeri, 4 «°. 



" 13. Pyrgodiscus armatus N.G. et. sp. Kitton, a. S.V. 4 ^°, b. 

 part of do. 10 f°, c. F.V. 4 f°, d. opposite valve of do.? 

 or abnormal form ? 

 " 14. Aotinocyclus (alienus ?) undatus, CI., 4 f°. 

 " 15. Melosira Omma CI., n.sp., 4 f°. 

 " 16. Podosira antediluviana CI., n.sp., 4 -2-°. 

 " 17. Coscinodiscus Thumii CI., n.sp. 

 " 18. Xanthiopyxis oblonga, 4 f °, a. F.Y. b. S.V. 



