890 Transactions of the Society. 



'A. oamaruensis Grove & Sturt, Journ. Quek. Mic. CL, 1887, p. 10, 



pi. iii. tig. i;j. 



Koundly, subregularly, elliptical, major axis from • 15 to • 23 mm., 

 1 1. to 1.^, times minor. {Surface with an elevated broadly obcordate 

 art'a between central space and processes, having the outer edge sharply 

 defined ; the transverse areas with edges sometimes less abrupt, outer 

 ends rounded at about 7/9 of radius from centre, and sides uniformly 

 concave. Colour pale brownish yellow, alternating with hyaline 

 strands. Central space diamond-shaped, large, hyaline. Markings 

 granular, closely aggregated in strands with hyaline interspaces, the 

 strands between the edges of the obcordate and transverse areas 

 distinct, the four sets together diamond-:-hapod ; those on the transverse 

 areas radial, expanding towards border, almost straight at the middle, 

 elsewhere convex towards the processes. Processes 2, large, rounded, 

 first expanding to median widest portion, and from this rounding 

 to apex ; from 0-02 to 0*03 mm. broad. — Sch. Atl., pi. cxvii. fig. 2, 

 pL cxxv. fig. 1. 



Habitat : Oamaru deposit (Grove & Sturt ! K. Eattray ! Hard- 

 man ! Kae !). 



A. intermedins Grove & Sturt in litt. 



Elliptical, major axis 0"1125 mm., about 1^ times minor. Surface 

 rising from centre towards processes, a transverse area at right angles 

 to the line of processes, distinct, with outer ends rounded at about 3/4 

 of radius from the centre, outside of this the slope to the border gentle. 

 Colour light smoky grey. Central space rounded, about ' 0125 mm. 

 broad. Markings granular, the strands separated by hyaline spaces, 

 those converging to the processes almost straight or slightly concave 

 outward towards the outer, sharply convex outward towards the inner, 

 ends, elsewhere almost straight, elongately obconical, towards the 

 processes confluent laterally. Border indistinct, striae delicate, 8 in 

 O'Ol mm. Processes 2, subcircular, about 0*015 mm. broad, with 

 the border opaque. — PI. XII. fig. 8. 



Habitat : Oamaru deposit ((J rove !). 



Var. simjjlex. — Major axis • 08 mm., about I^q times minor. 

 Markings : the strands narrower and of more uniform width, those 

 convei'ging to the processes more concave towards the central space, 

 the inner ends of those on transverse median areas more distinct, 

 around each process an irregular slightly angular band of large 

 unequal granules. Processes round, simple, 0*015 mm. broad, their 

 circumference with minute irregularities. — PI. XVI. fig. 5. 



Habitat : Oamaru deposit (Kae ! Grove !). 



§ 13. Sign ATI. 



The central portion of the valve sometimes distinct, transverse 

 areas indistinct, short or reaching close to border. Markings delicate 

 close strife around border, convex towards processes, sometimes 

 punctate. 



