A Revision of the Genus Aulaeodisciis Ehrb. By J. Rattray. 367 



circumference, constriction shallow and wide, placed towards base. 

 PL VII. fig. 1. Transitional to A. carruthersianus. 



Habitat : Newcastle deposit, Barbadoes (Firth ! Griffin !). 

 Var. circumdata. A. circumdatus, Sch. Atl., pi. xxxv. fig. 5. — 

 Small. Surface with inflations sharply defined and rounded at outer 

 ends. Central space quadrate, 1/18 to 1/20 of diam. broad. Mark- 

 ings, apiculi few, distinct, confined to inflations and raised central area. 

 Border, irregular, inner edge defined by a distinct dark line with 

 slight curves between the irregular dark radial lines passing to its 

 outer edge, striae delicate. Processes 4, insertion about 1 /3 of radius 

 from circumference, free ends knob-like, constriction acute. — The scar 

 of broken-off process is obviate. 

 Habitat : California (Griindler). 



Var. rara. — Diam. ■ 0575 to ■ 1025 mm. Surface flat to about 

 1/3 of radius, inflations less elevated, edges more straight. Markings 

 8 to 10 in ' 01 mm., apiculi minute on central area, near processes 

 fewer than in type. Processes 4, insertion about 1/4 of radius from 

 circumference. — PL VII. fig. 2. The scar of the broken-off process is 

 elliptical. 



Habitat: Newcastle deposit, Barbadoes ( Weissflog ! ) ; Cambridge 

 deposit. Barbadoes (Greville ! Johnson !). 



A. macraeanus Grev., Trans. Mic. Soc. Lond., 1862, p. 23, pi. ii. 

 fig. 4._Diam. 0*075 to 0*17 mm. Surface flat to about 1/4 of 

 radius, thence primary rays rising gradually for about 3/5 of length, 

 thereafter flat, or descending slightly to processes ; inflations at outer 

 ends merging gradually into peripheral area, a slight depression about 

 middle of each compartment. Colour pale smoky grey. Central space 

 minute, angular, 1/35 to 1/60 of diam. broad. Markings polygonal, 

 7 to 8 in 0-01 mm., increasing slightly to depressions on compart- 

 ments, again decreasing to border; apiculi inconspicuous on raised 

 central area, numerous and distinct on inflations and near the border. 

 Primary rays with rows in contact. Border striae 8 to 10 in • 10 mm., 

 1/15 to 1/20 of radius broad. Processes 3 to 5, insertion 1/4 to 2/5 

 of radius from circumference, hourglass-shaped, constriction median. 

 —Sch. Atl., pi. civ. fig. 2. 



The scar of broken-off process is oval and minute. 

 Habitat : Ceylon (Macrae ! Weissflog !) ■ Gazelle Exp. loc. (?) 

 (Weissflog!); Tamatave (Hardman!); sounding off Philippine 

 Islands 705 fms. (Eae !). 



A. excavatus Sch. Atl., pi. xxxvi. fig. 10. — Diam. 0*075 to 

 • 175 mm. Surface flat for about 1/10 of radius, thence primary 

 rays rising to processes, sides of inflations straight or slightly concave 

 outwards, somewhat abrupt, a broad basin-like depression at middle of 

 each compartment, deepest at about 1/3 of radius from border. Colour 

 pale grey, or blue at depressions, dark grey at border. Central space 

 round to quadrate, 1/11 to 1/12 of diam. broad, hyaline. Markings 

 round, 4 to 6 in * 01 mm., widest at depressions, interspaces hyaline, 

 secondary oblique rows evident on depressions. Primary rays with 



