350 Transactions of the Society. 



irregularly angular, indistinct, 1/27 to 1/35 of diam. broad, edges 

 uneven. Markings mostly hexagonal, largest about semiradius, 4 in 

 - 01 mm., decreasing gradually to border, central dot indistinct; 

 rows straight, secondary rows inconspicuous, rarely with large irregular 

 clear spaces around central space. Primary rays distinct, the areolae 

 more regular than those on compartments, increasing for 1/2 to 2/3 

 of radius, thence diminishing towards processes. Border striae monili- 

 form, 6 in 0"01 mm., in part continuous with radial rows. Processes 

 5 to 7, insertion 1/5 to 1/7 of radius from circumference, minute sub- 

 clavate, free ends rounded or truncate, no clear space at base. — 

 A. decorus Grove & Sturt, ibid., 1887, pp. 8, 146. 



Habitat : Oamaru deposit, New Zealand (Grove & Sturt !). 



A. radiosus Grove & Sturt, Journ. Quek. Mic. CI., 1887, p. 140, 

 pi. xii. fig. 33. — Diam. • 19 to 0*27 mm. Surface flat for about 1/3 

 of radius. Colour pale bluish grey, or darker at centre and border. 

 Centre with an irregular inconspicuous rosette 1/25 to 1/72 of diam. 

 broad, formed by unequal areolae. Markings polygonal, 4 in • 01 mm., 

 central dot faint, rows somewhat convergent only about processes. 

 Primary rays inconspicuous, recognized towards centre only when 

 traced inwards, the rows diverging slightly near outer ends. Border 

 striae 12 in 0*01 mm., 1/25 to 1/36 of radius broad, its inner edge 

 indistinct. Processes 5 to 7, insertion about 1/5 to 1/8 of radius from 

 circumference, clavate, constriction wide, shallow, clear space at base 

 small, rounded. 



The scar of the broken-off process is obovate. 



Habitat : Oamaru deposit, New Zealand (Grove & Sturt !). 



A. crux Ehrb., Mon. Ber. Ak., 1844, p. 76.— Diam. 0-0875 to 

 • 0925 mm. Surface flat along primary rays to processes, and to 

 about 1 /2 of radius on compartments ; inflations rudimentary, inter- 

 vening concavities distinct, shallow. Colour pale grey, darker towards 

 centre and border. Central space angular or elongate, 1/28 of diam. 

 broad, hyaline, rarely sub-obsolete. Markings polygonal, 4 in 

 0*01 mm., central dot faint, rows at centre of compartments together 

 forming an indistinct cruciform figure, alternate with rays, secondary 

 rows evident on inflations, sometimes irregular and indistinct. Primary 

 rays distinct, cruciform, rows diverging in outer 2/5 of their length. 

 Border indistinct, striae coarse, continuous with radial rows. Pro- 

 cesses 4, insertion 1/7 to 1/8 of radius from circumference, minute 

 free ends, rounded, clear space at base minute. — Ehrb. Mikrog., p. 8, 

 pi. xviii. fig. 47 ; Grunow, Denk. Wien. Ak., 1884, p. 69 ; Sch. Atl., 

 pi. xxxiii. fig. 3. Eupodiscus crux Kiitz., Sp. Alg., p. 135. 



The scar of the broken-off processes is elliptical or obovate. 

 Affinity to A. Comberi, pointed out by Ealfs, is remote. 



Habitat: Kichmond, Virginia (Kinker ! Weissflog !) ; Petersburg, 

 Virginia (Ehrenberg) ; Sta. Barbara deposit (Rae !) ; Szent Peter 

 deposit (Grove !) ; Simbirsk Polirschiefer (Cleve !). 



Var. subsquamosa Grun. MS. — Diam. 0"0775 to - 19 mm. 

 Surface with outer edge of elevated area more distinct, inflations more 



