876 Transactions of the Sociefij. 



A. antiquus sp. n. 



Eoundly elliptical, major axis 0"125 mm., 1^ times minor. Sur- 

 face rising sliglitly to processes, outlines of elevated areas between 

 central space and processes obconical, irregular and acutely angular, 

 those of transverse median areas indistinct, but outer ends slightly 

 convex and irregularly angular. Colour pale grey. Central space 

 indistinct, sides deeply concave outwards. Markings obscure, short 

 faint strife visible around the processes, a few irregular costate lines 

 at the outer ends of the transverse, and between adjacent sides of these 

 and the obconical areas ; apiculi minute, irregular between the eleva- 

 tions. Processes 2, uniformly convex, about 0'02 mm. broad. — 

 PI. XIII. fig. 4. 



Habitat : {Santa Monica deposit (Rae !). 



A. decoratus sp. n. 



Eoundly elliptical, major axis 0"15 mm., about 1^ times minor. 

 Surface with obconical elevated areas around processes well marked, 

 their sides straight or slightly concave, extending to the border ; the 

 transverse median areas of same size as foregoing, but with outer 

 angles somewhat more obtuse. Colour pale grey. Central space 

 0"0175 mm. broad, inconspicuous, sides deeply concave outwards, the 

 angles obtuse, more protuberant on the transverse areas than towards 

 the processes. Markings delicate punctate, in flexuous lines on the 

 transverse and obconical areas, and in less evident straight oblique 

 lines between their inner ends ; elsewhere irregular ; apiculi absent ; 

 around the outer edge an irregular band of radially elongate or rounded 

 prominent pearly markings, sometimes double and extending farthest 

 inwards between outer ends of transverse and obconical areas, a single 

 less evident straight baud passing from each angle of the obconical 

 areas and meeting at a short distance within the processes on a line 

 joining them with the centre. Processes 2, small, with free ends 

 obtuse.— PI. XII. fig. 6. 



Habitat : Santa Monica deposit (Rae !). 



Var. «Ji?«s. — Major axis from 0-0925 to 0-22 mm., 11 to 

 l^^Y times minor. Markings more distinct, scabrous, those in the 

 prominent band at border extending less deeply inwards between the 

 transverse and obconical areas, no bands meeting on the obconical 

 areas within the processes. Processes larger, more protuberant, sides 

 concave outwards, free ends rounded. — PI. XVI. fig. 1. 



This var. is intermediate between A. decoratus and A. hard- 

 maniamis. 



Habitat : Santa Monica deposit (Rae !) ; Santa Maria deposit 

 (Rae!). 



A. eximitis sp. n. 



Roundly elliptical, major axis 0'0925 mm., about 1| times minor. 

 Surface rising slightly at processes, obconical areas around the latter 



