358 Transactions of the Society. 



darker at processes. Central space rounded, 1/14 to 1/22 of diaru. 

 broad. Markings round or bluntly angular, oval and oblique about 

 processes, 2^ to 3^ in O'Ol mm., interspaces largest towards centre, 

 punctate, rows subradial or more parallel, slightly bent at origin of 

 shorter rows. Primary rays sometimes distinct, the rows diverging 

 but little near processes. Border indistinct, rarely a clear space next 

 its inner edge. Processes 5 to 11, insertion 1/5 to 1/9 of radius from 

 circumference, cylindrical, tapering near base, constriction median, 

 slight, free ends rounded. — Sch. Atl, pi. xxxiv. fig. 6; pi. xli. fig. 13. 

 A. pellucidus Grev., ibid., 1864, p. 12, pi. i. fig. 5 ; A. amoenus var. 

 sparso-radiata Grove & Sturt, Journ. Quek. Mic. CL, 1887, p. 9. 



Habitat : Cambridge deposit, Barbadoes (Johnson ! Firth !) ; 

 Oamaru deposit (Grove & Sturt !) ; Japan (Grundler). 



Var. hungarica Pant., Fossil. Bacil. Ung., p. 57, pi. ii. fig. 13. — 

 Diam. 0*085 mm. Surface flat to 1/2 of radius, highest zone 1/4 of 

 radius broad, concavities between processes deep. Central space 

 1/19 of diam. broad, slightly excentric. Markings polygonal, 5 in 

 O'Ol mm., rows subradial, not deflected at processes. Primary rays 

 distinct. Processes 7, insertion 5/17 of radius from circumference, 

 shorter and broader, clear area at base small. 



Habitat : Szent Peter deposit (Pantocsek !). 



Var. subdecora, — Diam. 0-075 to 0*12 mm. Surface rising for 

 3/5 to 5/8 of radius, outer edge polygonal with angles at centre of 

 compartments and sides straight, a second polygonal figure more distinct 

 with angles at processes, intervening area flat. Central space 1/15 to 

 1/19 of diam. broad, hyaline. Markings 5 in - 01 mm., rows often 

 flexed at periphery. Primary rays inconspicuous. Border stride 

 10 to 12 in • 01 mm. Processes 5 or 6, insertion 1/5 to 1/6 of radius 

 from circumference, proximal portion bulb-like, distal cylindrical — 

 PI. VII. fig. 5. 



Habitat : Cambridge deposit, Barbadoes (Johnson !). 



Var. minor Grove & Sturt MS. — Diam. 0*06 mm. Surface 

 highest and flat from centre to 7/12 of radius, adjoining zone angu- 

 lar at processes, between these sides convex, inflations inconspicuous. 

 Central space quadrate, 1/24 of diam. broad, delicately punctate. 

 Markings 4 in 0"01 mm. Primary rays cruciform. Border striae 

 8 in 0*01 mm., sometimes indistinct, within it a narrow clear space. 

 Processes 4, insertion 1/4 of radius from circumference, proximal 

 portion rounded, distal infundibulate or slightly convex. 



Habitat : Oamaru deposit (Grove !). 



A. oregonus Harv. & Bail. Proc. Acad. Nat. Sci. Phil., 1853, 

 p. 430. — Diam. ■ 075 to ■ 235 mm. Surface flat or slightly con- 

 cave at centre, highest zone 1/4 to 1/8 of radius broad. Concavity 

 between processes deep, rarely shallow. Colour light blue or slaty 

 grey. Central space rounded, rarely subquadrate, 1/16 to 1/20 of 

 diam. broad, granulate. Markings round, 4 in 0*01 mm., with finely 

 granulate interspaces towards centre, rows parallel on each com- 

 partment. Primary rays distinct, rows diverging slightly in outer 



