A Revision of the Genus Aulacodiscus Ehrb. By J. Rattray. 359 



half. Border striae 12 in O'Ol mm., about 1/35 of radius broad, 

 inner edge distinct. Processes 6 to 27, usually 9 to 20, insertion 1/6 

 to 1/7 of radius from circumference, subcylindrical, margins slightly 

 convex. — A. oreganus Grev., Quart. Journ. Mic. Sci., 1859, p. 156, 

 pi. vii. fig. 2 ; Sch. Atl., pi. xxxiv. figs. 4-5 ; A. oregonensis Bail. 

 & Harv., Wilkes, Explor. Exp. § Algfe, vol. xvii. p. 176, pi. ix. fig. 6. 

 In 1856 Greville received authentic specimens — now in British 

 Museum — from Bailey. In smaller valves the elevation extends to 

 the centre, the number of primary rays is less, but the central space 

 not always so. 



Habitat : Puget Sound, Oregon (Harvey and Bailey ! Greville !) ; 

 California (Greville ! Arnott ! Weissflog ! Gnindler) ; California on 

 Polysiphonia (Kitton ! Kinker !) ; on marine algae (Ptae !) ; among 

 shell scrapings (Dickie ! Grove !) ; Bodega Bay, California (Bailey) ; 

 South Sea Islands (Greville !) ; on Ealiotis shell, loc. (?) (Stokes !) ; 

 on Ecdiotis shell, Peru (Grove); California guano (Greville!); 

 Monterey stone (Pialfs, Cleve !) ; Los Angeios, California (Cleve !). 



A. intumescens sp. n. — Diani. ■ 29 mm. Surface slightly concave 

 at centre ; highest zone at processes, with sides distinct, the outer bluntly 

 angular at processes, almost straight on compartments, abrupt, 

 beyond this a narrow somewhat steep zone with deep concavities on 

 outer side of each process, and sides convex opposite compartments, 

 border at a much lower level ; inflations slight. Central space round, 

 about 3/6 of diam. broad, puncta most marked at centre. _ Markings 

 within highest zone round, outlines faint, central dot distinct, clear, 

 1\ to 3 in 01 mm., on highest zone more distinct crowded, inter- 

 spaces punctate, largest at inner ends of short rows, rows slightly 

 deflected at processes. Primary rays distinct, interspaces narrow. 

 Border with a single band of granules 4 to 5 in O'Ol mm., at its 

 inner side a narrow minutely punctate space. Processes 15, conical, 

 sides slightly concave, large, free ends truncate, at base of each a 

 brilliant round clear spot. — PI. V. fig. 6. 

 Habitat : Oamaru deposit (Doeg !). 



A. affinis Grun., Sch. Atl., pi. xxxiv. figs. 9, 10 ; pi. cvii. fig. 7.— 

 Valves rarely elliptical. Diam. 0'12 to 0*47 mm. Surface flat to 

 about 4/9 of radius, thence rising to highest zone at processes, con- 

 cavities between latter distinct. Colour, centre greenish yellow, bluish 

 about semiradius, pale or dark grey at border. Central space round, 

 1/14 to 1/23 of diam. broad, granulate. Markings rounded, 4 rarely 

 2 in • 01 mm., compressed towards border, interspaces punctate or 

 granulate, secondary irregular subconcentric bands obvious towards 

 central space. Primary rays indistinct, space between the rows en- 

 larging near processes. Border granules 6 in 0" 01 mm., striae beyond 

 these sometimes only present, 1/24 to 1/52 of radius broad. Processes 

 5 to 27, insertion 1/6 to 1/13 of radius from circumference, constriction 

 as in A. oregonus. — A. Lumjaeseldi f. minor Pant., Fossil. Bacil. Ung., 

 p. 59, pi. i. fig. 2, pi. xxv. fig. 229 ; A. Lunyacsekii f. major jpolygona 

 et polygilba Pant, in litt. ; A. Lunyacsehii f. maxima Pant., ibid., 



