A Revision of the Genus Aulacodisous Ehrb. By J. Rattray. 363 



Var. stellata. — Diam. # 12 Him. Central space quadrate, 1/32 of 

 diani. broad, inner ends of stellette meeting at its middle. Mark- 

 ings most distinct about outer 2/5 of radius. Central stellette 4-rayed, 

 each ray ovate with narrow end passing through angles of central 

 space, • 02 mm. long. Border striae lOto^inO^Ol mm. Processes 

 4, insertion 1/5 of radius from circumference. — PI. VII. fig. 3. 



Habitat : Cambridge deposit, Barbadoes (Johnson !). 



A. mammosus Grev., Trans. Mic. Soc. Lond., 1863, p. 70, pi. iv. 

 fig. 13. — Diam. 0*0775 to - 16 mm. Surface, central portion flat 

 to 1/3 or 1/4 of radius, outer edge distinct, concave, primary rays 

 rising gradually for 1/2 to 2/3 of length, then more steeply to pro- 

 cesses ; inflations with distal ends prominent and rounded. Colour 

 pale smoky grey. Central sj>ace quadrate, rarely rounded, 1/11 to 

 1/16 diam. broad, hyaline, rarely with a few granules. Markings 

 polygonal, rounded near central space, 4 in • 01 mm., rows straight 

 and radial on inflations and at middle of compartments, elsewhere 

 somewhat sigmoid, the greater flexure concave towards primary rays 

 at outer end. Primary rays distinct to central space. Border striae 

 moniliform, 6 in 0*01 mm., 1/15 to 1/20 of radius broad, inner edge 

 indistinct. Processes 4, insertion 1/5 to 1/7 of radius from circum- 

 ference, cylindrical, sides convex towards base, free ends convex. — ■ 

 Walker and Chase, New and Eare Diats., p. 4, pi. ii. fig. 11. 



The scar of the broken-ofT process is obovate. 



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

 Newcastle deposit, Barbadoes (Firth !). 



Var. extans. A. extans Grev., Trans. Mic. Soc. Lond., 1864, p. 87, 

 pi. xii. fig. 1. — Diam. 0'215 to - 32 mm. Surface with primary 

 rays rising more uniformly to processes, but somewhat more steeply in 

 peripheral 1/3, inflations more abrupt. Central space round, clear, 

 about 1/17 of diam. broad. Markings, apiculi most distinct on in- 

 flations, sides concave, apices acute. Border striae 8 in • 01 mm., 

 1/24 to 1/25 of radius broad, inner edge distinct. Processes 4 or 5, 

 insertion 1/9 to 1/25 of radius from circumference. 



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

 Newcastle deposit, Barbadoes (Firth !). 



A. Janischii Grove & Sturt, Journ. Quek. Mic. CI., 1887, p. 139, 

 pi. xi. fig. 28. Diam. ■ 125 to 0'425 mm. Surface with inflations 

 rising gradually to processes, sharply defined for outer 3/10 to 1/2 of 

 length, at middle of compartments narrow, radial, clear areas distinct. 

 Colour pale to dark grey. Central space elliptical to angular, 1/16 

 to 1/24 of diam. broad, punctate. Markings polygonal but round 

 towards centre, 3 J to 4 in • 01 mm., outlines delicate, interspaces 

 punctate, rows in curves round inflations. Primary rays with rows 

 diverging in outer 1/2 of length. Border striae 10 to 12 in 0*01 mm., 

 1/50 to 1/85 of radius broad, sometimes with 2 concentric bands of 

 oval granules. Processes 7, rarely 6, insertion 1 /6 to 1 /9 of rati ius from 

 circumference, proximal and distal parts subequal, constriction slight. 

 — A. Janischii var. abrupta Grovo & Sturt, ibid., p. 139 ; A. in- 



