A Revision of the Genus Aulacodiscus Ehrb. By J. Rattray. 365 



The scar of the broken-off process is elliptical. 



Habitat : Auckland Islands, New Zealand (Schmidt !) ; Whangarei, 

 New Zealand (Rae !). 



Var. late-injlata nov. — Diam. ■ 09 to ■ 1 1 mm. Surface with 

 inflations much wider, its edges abrupt. Central space quadrate, 1/19 

 to 1/38 of diam. broad. Border less distinct on its inner side. Pro- 

 cesses 4, insertion 1/3 to 3/8 of radius from circumference. 



Habitat : Whangarei, New Zealand (Rae !). 



A. Wittii Janisch, in Sch. Atl, pi. cvi. figs. 1, la. — Diam. 

 0*365 mm. Surface, inflations low, wide, obovate, with edges distinct 

 but not abrupt. Central space subquadrate, about 1/48 of diam. broad, 

 hyaline, its angles at middle of apices of compartments. Markings 

 polygonal, or rounded close to central space, interspaces absent, rows 

 in wide curves on inflations, secondary oblique rows well-marked. 

 Apiculi few, only around, and chiefly on central side of processes. 

 Primary rays cruciform, rows in contact. Border striae distinct, 8 in 

 "01 mm., about 1/19 to 1/24 of radius broad, its inner edge definite, 

 a narrow sharp line close to inner edge and concentric with it. Pro- 

 cesses 4, insertion about 1/3 of radius from circumference, proximal 

 portion rounded minute, distal large, rounded, striated, sometimes 

 with a small terminal knob, clear space at their base, irregular, well- 

 marked. 



Habitat : Simoda, Japan (Witt). 



A. cinctus Grev. MS. — Diam. 0*08 to 0*14 mm. Surface flat 

 for 1/3 to 3/8 of radius, thence primary rays rising gradually to 

 processes, outer ends of inflations sharply defined. Colour pale grey. 

 Central space 3-4-angled, 1/14 to 1/21 of diam. broad. Markings 

 polygonal, 4 in 0*01 mm., rounded, with narrow clear interspaces 

 about middle of compartments, rows widely curved towards processes. 

 Apiculi round, many, placed irregularly over inflations beyond flat 

 central area, on this area rare, absent from intervening portions of com- 

 partments. Primary rays with rows in contact. Border striae 8 in 

 0*01 mm., 1/16 to 1/19 of radius broad, inner edge distinct, near 

 outer a dark line, prominent small protuberances with rounded outer 

 ends at its outer edge. Processes 4, insertion 1/4 to 1/5 of radius 

 from circumference, proximal portion longer than distal, constriction 

 well marked, free ends rounded, no clear space at base. — A. injiatus 

 Grev., Sch. Atl., pi. xxxv. fig. 9, pi. cvii. fig. 5. 



Habitat : Cambridge deposit, Barbadoes (Johnson ! Greville ! 

 Hardman ! Weissflog !) ; Newcastle deposit, Barbadoes (Firth !). 



A. Petersii Ehrb., Mon. Ber. Ak., 1845, p. 361.— Diam. 0-0825 

 to 0*195 mm. Surface flat for about 1/4 of radius, thence rising 

 along primary rays to process, outer ends of inflations just beyond 

 the processes distinct, compartments within and near zone of processes 

 almost flat ; slope to border gentle. Colour pale grey, darker about 

 central space, middle of compartments and processes. Central space 

 quadrate, more rarely triangular, 1/20 to 1/40 of diam. broad, sides 

 opposite ends of primary rays. Markings polygonal, mostly hexa- 



