A Revision of the Genus Aulacocliscus Ehrb. By J. Rattray. 369 



insertion 1/7 to 5/17 of radius from circumference, hourglass-shaped, 

 but proximal portion the larger. 



The scar of the broken-off process is oval. 



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



A. Lahuseni Witt, Simb. Polirsch., p. 20, pi. vi. fig. 9, pi. vii. fig. 5. 

 — Diam. 0-1275 mm. Surface flat to about 17/25 of radius, with 

 outer edge round, passing abruptly into highest zone, the latter about 

 4/25 of radius broad, slightly convex, its outer edge circular, more 

 abrupt, bearing a narrow ridge with minute undulations ; slope to 

 border steep. Colour pale grey. Central space absent. Markings 

 round or bluntly angular, 3£ in 0-01 mm., smaller and more crowded 

 on inner portion of highest zone, at middle of this zone again larger, 

 with more unequal interspaces, interspaces hyaline, widest towards 

 centre, rows radial, straight, interrupted, and not traceable near centre. 

 Primary rays distinct, straight, cruciform, rows interrupted. Border 

 strife faint, 8 in • 01 mm., indistinct. Processes 4, insertion about 

 1/6 of radius from circumference, cylindrical or subinfundibulate, 

 sides concave, in oblique aspect conical, free ends tunicate. — Sch. Atl., 

 pi. ci. fig. 5. 



Habitat : Simbirsk Polirschiefer (Witt !). 



Var. marginalis Witt, ibid., p. 21, pi. vii. fig. 3.— Diam. 0*105 

 mm. Surface flat to about semiradius, adjoining this a zone rising 

 gently to highest zone, the latter about 1/10 of radius broad, both 

 edges indistinct, circular, slope to border more gradual. Colour more 

 clear, outer part pale grey. Markings on central portion more 

 minute, on adjacent zone moniliform, 6 in 0" 01 mm., on highest zone 

 irregular. Primary rays with rows wider, sometimes markings on 

 highest zone are continued across the rays. Border 1/28 of radius 

 broad. Processes 4, insertion 1/4 of radius from circumference. — 

 A. Lahusenii var. marginata, Sch. Atl., pi. ci. fig. 4. 



Habitat : Simbirsk Polirschiefer (Witt !). 



Var. punctata Witt, ibid., p. 20, pi. vii. fig. 4.— Diam. 0-165 mm. 

 Surface flat to about 8/11 of radius, outer edge less distinct, highest 

 zone about 1/11 of radius broad, outer edge sharply defined, slope to 

 border short, steep. Colour as in var. marginalis. Markings round 

 or oval towards centre, towards outer edge of central portion more 

 crowded, 6 in 0'01 mm., at middle of highest zone irregular, 

 elliptical, sometimes granular and minute, rows inconspicuous, but 

 traceable to centre. Primary rays less distinct, rows more regular, 

 not interrupted. Processes 6, insertion 1/7 to 1/8 of radius from cir- 

 cumference. — Sch. Atl., pi. ci. fig. 6. 



Habitat : Simbirsk Polirschiefer (Witt !). 



Var. hyalina. — Diam. ■ 1 mm. Surface, central portion flat to 

 about 3/5 of radius and on a plane with border, its outer edge sharply 

 defined, adjacent zone between processes convex, its outer edge less 

 distinct. Markings on central area round, minute, irregular in radial 

 rows, but absent from its outer portion, on adjacent zone closely 

 disposed, submoniliform. Primary rays interrupted by hyaline zone 

 1888. 2 d 



