346 Transactions of the Society. 



Habitat : Teneriffe (Norman ! Hardman ! Weissflog !) ; ' Gazelle,' 

 Exped. (Weissflog !). 



A. spectabilis Grev., Trans. Mic. Soc. Lond., 1863, p. 71, pi. v. 

 fig. 16. — Diam. 0*075 to 0*1225 mm. Surface rising to 1/3, or flat 

 to about 1/4 of radius; highest zone about 1/5 of radius broad, 

 straight, or slightly concave outwards on compartments; inflations 

 extending to border, tapering but slightly inwards, their edges abrupt ; 

 slope to border gentle. Colour pale grey, darker about primary rays 

 and middle of compartments. Central space pentagonal, 1/16 to 

 1/25 of diam. broad, sides convex inwards, hyaline. Markings oval 

 or bluntly angular, 6 in '01 mm., least crowded towards centre, 

 decreasing but slightly towards border, rows transverse or oblique 

 on inflations. Primary rays distinct only outside highest zone where 

 the rows suddenly diverge, again converging somewhat towards pro- 

 cesses. Border striae 10 in 0*01 mm., 1/21 to 1/24 of radius broad, 

 a narrow clear area between it and the radial rows. Processes 5, 

 insertion 1/4 to 1/5 of radius from circumference. Constriction 

 median, distinct, free ends convex. — A. gromdis Walker, New and 

 Bare Diats., p. 3, pi. i. fig. 8. The scar of broken-off process is 

 oval. 



Habitat : Cambridge deposit, Barbadoes (Greville ! Johnson !). 



Var. depressa. — Diam. 0*115 mm. A small, rounded depression 

 on compartments near outer edge of highest zone, and about 1/12 of 

 radius broad. Markings rounded, 6 to 8 in ' 01 mm., faintly traceable 

 across depressions, more irregular near central space. Primary rays 

 with wider median space. Processes 5, ends truncate. — PI. VII. fig. 6. 



Habitat : Cambridge deposit, Barbadoes (Johnson !). 



A. quadrans Sch., Atl., pi. xxxv. fig. 10. — Diam. 0*1125 mm. 

 Surface, central portion fiat to 1/8 of radius, with outer edge distinct, 

 round or somewhat irregular ; primary rays on same plane to pro- 

 cesses, inflations distinct, compartments flat for about outer 2/3 of 

 radius from border. Colour pale grey. Central space irregularly 

 quadrate, 1/22 of diam. broad. Markings polygonal, rounded close 

 to central space, outlines delicate, 5 in * 01 mm., rows straight, radial, 

 secondary rows distinct on raised areas. Primary rays well marked, 

 rows diverging for 1/3 of length from inner ends, thence remaining 

 parallel or converging but slightly towards processes. Border narrower 

 by about 1/2 opposite processes, hyaline, about 1/23 of radius broad. 

 Processes 4, insertion about 2/11 of radius from circumference, obovate 

 or subclavate, beyond distal ends a subcrescentic line sometimes 

 visible, clear space at base large, sometimes asymmetrical. 



Habitat : Simbirsk Polirschiefer (Weissflog !). 



A. dispersus sp. n. — Diam. 0*15 to 0*175 mm. Surface, central 

 portion flat for about 1/5 to 4/9 of radius, with outer edge slightly 

 convex on compartments, and angular at primary rays. Central 

 space quadrate, indistinct, about 1 /40 of diam. broad. Markings poly- 

 gonal towards centre, rounded towards border, 4 to 6 in 0*01 mm., 

 outlines indistinct, central dot minute, rows radial, straight, separated 



