906 Transactions of the Society. 



central portion witli numerous evident radial subpruinose strife, some- 

 times fasicnlato, and meeting; at their centre or leaving an elongate 

 narrow hyaline space, their border narrow, hyaline, their circumference 

 smooth. 



Habitat : Sysran deposit (Grove !) ; " Simbirsk " (Thum). 



P. fulvinaius Cleve, Journ. Quek. Mic. CL, 1885, p. 171, pi. xii, fig. 9, 



Subcircular or circular, diam. from 0'0675 to 125 mm. Sur- 

 face rising shghtly from the centre for 1/4 to 3/5 of radius to the 

 hif'hest zone, this zone from 1/3 to 1/12 of radius broad, with shallow 

 median depression, its edges indistinctly defined, sometimes passing 

 on the outer side of the processes, slope to the border gentle. Colour 

 pale smoky grey, darker around the edges of the highest zone. 

 ]\larkings minute, punctate, in indistinct irregular radial lines, those 

 converging to the processes short, a series of faint, frequently ana- 

 stomosing, hyaline lines sometimes present, most evident about the 

 hi<^hest zone ; apiculi few, near the border and about midway between 

 the processes, sometimes absent. Processes 2 or 3, rounded, from 

 O'O025 to 0'0075 mm. broad, their circumference sometimes rough. 

 — Pant. Fossil. Bacil. Ung., p. 50. pi. xix. figs. 174, 175, 177. 

 A. imlvinatus var. ? Grun. in Sch. AtL, pi cxxv. fig. 17. 



In small valves the elevated zone is sometimes indistinct. Pantoc- 

 sek has distinguished. as forma appiculata and forma ^?^enn^s specimens 

 with and without the marginal apiculi respectively. Specimens of the 

 latter with three processes he has named forma inernus triocellafa. 



Habitat: Kekko deposit (Pautocsek ! Kinker ! Weissflog I) ; Szent 

 Peter, iSzakal, and Felso-Estergaly deposit (Pantocsek !) ; Sysran 

 deposit (Thum !*) ; Miihren deposit, Austria ( I'hum !*). 



P. Petiti Leud.-Fort. Diat. Ceyl., p. 64, pi. viii. fig. 76. 



Circular, diam. 0*0875 to 0*1225 mm. Surface flat from centre 

 to about semiradius, thence sloping gently to the border. Colour 

 pale yellowish grey, darker about the semiradius. IMarkings, delicate, 

 minute areolae ; rows straight, radial ; secondary oblique decussating 

 rows distinct ; apiculi close to the border, distant, usually from 3 to 7, 

 occurring between each process. Border opaque, sharply defined on 

 its inner edge, narrow. Processes 3, irregularly and transversely 

 elhptical, about 0*0075 mm. broad. — Eupodiscus ohsctirus Grev., 

 Trans. Mic. Soc. Lond., 1862, p. 90, pi. ix. fig. 4. 



Habitat: Ceylon (Leuduger-Fortmorel, Kitton ! Macrae!); Cajje 

 of Good Hope (Macrae !). 



P. letonensis Janisch, Sch. Atl., pi. Ixvii. fig. 14. 



Cu'cular, diam. 0"03'i mm. Surface convex. Markings, delicate 

 areolae, 6 to 8 in 0*01 mm., rows straight, radial; secondary oblique 

 decussating rows evident, striae converging to the processes absent. 



* In the Collection of Mr. Julion Duby. 



