456 
Proceedings of Royal Society of Edinburgh. [sess. 
about i of the radius broad ; rows irregular. Border sharply defined, 
with widely placed subcostate striae hardly extending to the 
circumference. — (PI. I. fig. 18.) 
Habitat. — Manilla (Firth !). 
C. megacoccus , Cstr. Diat. Ghall. Exped ., p. 162, pi. xvii. fig. 2. 
— Diam. *041 mm. Central space absent. Markings polygonal, 
1 J to If in *01 mm., unequal. Border formed by a single band of 
4-angled areolae, with inner edges somewhat convex inwards, 3 in 
*01 mm. 
In the large size of the markings this species approaches 
Stephanopyxis. From C. marginafus it is distinguished by its 
more irregular marking and the marginal band of areolae. 
Habitat. — Pacific Ocean (Castracane). 
C. nottingliamensis , Grun. Van Heurck., Syn. Diat . Belg ., pi. 
cxxix. fig. 2. — Diam. *0165 mm. Central space absent. Markings 
polygonal, about 3J in *01 mm., decreasing slightly outwards. 
Border about ^ of radius broad, with closely placed radial striae ; 
apiculi long, delicate, numerous, inserted at inner edge of border, 
but extending beyond the circumference. 
Habitat. — Nottingham deposit (Van Heurck). 
C. antediluvianus, sp. n. — Diam. *1125 mm. Surface almost 
flat, slightly convex towards the border. Central space absent. 
Markings irregularly areolate, 4 to 5 in '01 mm., on the outer third 
of radius decreasing uniformly but somewhat rapidly to 8 in *01 mm. 
at the border; apiculi prominent close to the border, inserted at 
unequal intervals, varying from *005 to '015 mm. Border 
indistinct, striae 6 to 8 in *01 mm.— (PI. I. fig. 12.) 
Habitat. — Santa Monica deposit (Grove !). 
C. spinulosus , Ehrb. Mon. Ber. Ak ., 1845, p. 154. — Elliptical. 
Diam. *047 mm. Surface flat, slightly convex. Central space 
absent. Markings angular, their edges slightly spinulose — about 
6 in *01 mm.; around the border a fringe of prominent closely 
disposed apiculi. — Ehrb., Mikrog ., pi. xxxviii. B. xxii. fig. 9. 
This is probably a Stephanopyxis. 
Habitat. — Fossil at Port Desire, Patagonia (Ehrenberg). 
