A Bevision of the Genus Auliscus Ehrh., &c. By J. Battray. 817 



distinct, their outer angles rounded, the transverse median areas 

 narrow, clavate. Colour hyaline, light grey around edges of these areas. 

 Central space inconspicuous, 0"015 mm, broad. Markings indistinct 

 punctate, in faint radiating lines diverging from centres of transverse 

 and obconical areas, elsewhere obscure ; apiculi few, irregular, chiefly 

 between the angles of these areas. Processes 2, roundly elliptical, 

 about • 02 mm. broad, around their base a series of evident parallel 

 strige.— PL XIII. fig. 2. 



Habitat : Santa Monica deposit (Eae !). 



A. hardmanianus Grrev., Trans. Mic. Soc, 1866, p. 6, pi. ii. fig. 17. 



Eoundly elliptical, major axis from • 075 to • 2 mm., about 1-^^ 

 to 1 ji^ times minor. Surface flat at centre. Obconical areas between 

 central space and processes, and the transverse sometimes narrower 

 areas rising slightly outwards, their sides sharply defined and outer ends 

 indistinct, the remaining portions flat to border. Colour pale grey. 

 Central space 0'0125 to 0'03 mm. broad. Markings prominent, 

 distant striae stretching between adjacent sides of obconical and trans- 

 verse areas, the striae around and at right angles to margins of these 

 areas numerous, distinct, traceable across about 1/3 of the intervening 

 portions, often curved at the outer ends, those around border more faint, 

 straight, or slightly convex towards the processes, irregular, distinct 

 puncta about middle of obconical areas and intervening spaces ; apiculi 

 sometimes present. Processes 2, conical free ends rounded, from • 015 

 to 0-025 mm. broad. — Sch. Atl., pi. Ixvii. fig. 1, pi. Ixxxix. fig. 4. 

 A. Joynsonii Sch. Atl., pi. Ixvii. fig. 2. A. hardmanianus var. (?), 

 Sch. Atl. pi. cviii. fig. 1. A. hardmanianus var. haytiana Truan 

 & Witt, Jerem. Diat., 1888, p. 12, pi. ii. fig. 4. 



In smaller valves the outer ends of the elevated areas bearing the 

 processes are greatly expanded and rounded. 



Habitat : Santa Monica deposit (Kinker ! Firth ! Cleve ! Hardman ! 

 Deby !) ; Santa Maria deposit (Eae !) ; Santa Barbara deposit (GriSin !) ; 

 Oamaru deposit (Grove ! K. Kattray !) ; Monterey deposit (Hardman) ; 

 Crescent City, California (Weissflog !) ; San Pedro (Grove) ; Los 

 Angelos, California (Hardman !). 



Var. futilis. — Elliptical, major axis • 075 mm., 1^ times minor. 

 Surface with transverse and obconical areas indistinct, outer ends of 

 former close to border. Centra] space with the angles on the trans- 

 verse area extending close to the outer end of this area. Markings 

 most evident on the transverse area, a few indistinct lines passing to 

 the edges of the area.3 around the processes. 



Habitat : Santa Monica deposit (Rae ! Firth !) 



Var. lahyrinthula. — Subcircular, diam. 0"0725 mm. Surface, 

 with outer ends of transverse areas, sharply defined. Markings dis- 

 tinct broad clear lines, convex towards the processes, radiating from 

 the angles at outer ends of transverse areas, and similar irregularly 

 curved lines passing between the angles of the adjacent transverse and 

 obconical areas, and sometimes anastomosing. Processes 2, one regu- 



1888. 3 o 



