172 r. T. CLEVE ON SOME FOSSIL MARINE DIATOMS. 



two, large, centre punctate depressed, surrounded by two elevated 

 rings, separated by a furrow. Structure : minute puncta, ar- 

 ranged in irregular radiating lines. Margin with a few short 

 apiculi. Diameter *08 mm. PI. 13, f. 9, ^~ 



AcTINOPTYCIIEuE . 



Actinoptychus undulatut, Ebr. Large specimens '08-. 18 mm. 

 in diameter. Between the three marginal nodules and the central 

 area are distinct raphes. 



A. splendens (Shadb.), Ralfs. Van Heurck Syn., PI. 119. Be- 

 sides the typical form I have observed the following varieties : — 



var. Californica, Grim. Van Heurck Syn., PI. 120, f. 1. 



var. Nicobarica, Grun., I.e., f. 4. 



A. glabratus, Grun, I.e., PI. 120, f. 6. 



var. incisa, Grun., I.e., f. 8. 



A, vulgaris, var. Virginica, Grun., I.e., PI. 121, f. 7. PI. 13, f. 

 11. Another variety occurs in the Tegel, having a coarser reticular 

 and more distant rows of puncta. PI. 13, f. 10. 



A. SimbirsJcianus, A. Schm. Atl., PI. 29, f. 11 (1875). One 

 specimen, resembling the figure in the Atlas. 



A. Boliviensis, Janiscb. A. Schm., Atl. PI. 1, f. 23 (1875). 

 One large specimen. I regard as varieties of this species — 



A. GriXndleri. A. Schm. Atl., PI. 1, f. 22 (1875). 



A. Pfitzeri, I.e., PI. 29, f. 1 (1875). 



The differences between the three forms consist in the number 

 of the marginal nodules, the form of the blank spaces, and the 

 depression of the surface, but all these characters are variable. In 

 PI. 13, f. 12, I give a figure of A. Pfitzeri, from the Tegel. 

 A. Grundleri has two nodules, and is larger, but does not other- 

 wise differ. 



A: Moronensis (Grev.), CI. Omphalopelta Moronensis, Grev. 

 T.M.S. xiv., p. 122, PI. 2, f. 14 (1866). This species does not 

 seem to be rare in the Tegel, and varies in size from -08-*26 mm. 

 in diameter. Small specimens agree with Greville's figure, but 

 the large valves are more flattened and are slightly hexagonal. 



Asterolampra Marylandica, Ehr. (1844). Diameter of valve 

 •11 mm., rows of puncta 8 in *01 mm. 



Thaumatodisci Cleve. 

 In this family I propose to include some very remarkable forms 

 of Diatomacea3, the valves of which have prominent central pro- 

 cesses. I place in this family the genera Tkaumatonema, Greville, 



