586 Proceedings of Royal Society of Edinburgh. [sess. 
rising from the centre for about \ of radius to the highest zone ; this 
zone convex, most sharply defined on its inner side, its outer edge 
passing gradually into the outer portion, which slopes downwards 
to the border. Central space subcircular, about of diam. broad, 
with a few isolated granules at its middle. Markings angular, 
towards the centre 8, on the highest zone largest, subpearly 5, 
beyond this subequal to the border and 6, in *01 mm.; secondary 
subconcentric bands evident on the highest zone, distinct subulate 
areas opposite origin of shorter rows about the semiradius; apiculi 
at the border evident, rarely obscure, at intervals of about *01 mm. 
Border narrow, hyaline. — 0. eiegans , var. spinifera, Grove and 
Sturt, Jour. Quek. Micr. Cl., vol. iii. ser. 2, 1887, p, 69, pi. v. fig. 9. 
Grunow justly separates this from C. eiegans , Grev.,but it is quite 
distinct from Cestodiscus pulchellus, Grev., to which he is inclined 
to assimilate it. 
Habitat. — Oamaru deposit (Doeg ! Grove !). 
C. griseus. Grev., Quart. Jour. Micr. Sci., 1863, p. 230, pi. ix. 
fig. 7. — Diam. *065 to "0825 mm. Surface rising slightly from 
centre to about semiradius, thence sloping gradually to the border. 
Central space rounded, to -f T of diam. broad, inconspicuous, 
bearing several rounded granules. Markings rounded, granular, 
6 in ’01 mm., decreasing slightly near the border ; the rows straight 
or slightly bent, the shorter rows irregularly placed ; interspaces 
narrow, minute ; apiculi at intervals of about *01 mm., sometimes 
inserted at the border. — Sch., Atl., pi. lviii. figs. 13, 14 (excl. fig. 1). 
Small hyaline irregular spaces sometimes occur here and there on 
the surface, and there may be a narrow clear band within the 
border. Sometimes confounded with C. apollinis. 
Habitat. — Cambridge deposit, Barbados (Greville ! Johnson !) ; 
Barbados (Cleve ! Birth!); Monterey (Weissflog!) ; Los Angelos 
(O’Meara!); Santa Maria deposit (Grove!); Santa Monica deposit 
(Cleve !). 
Yar. apiculata, nov. — Diam. *0875 mm. Similar to the type, but 
the markings increasing from the central space outwards ; towards 
the centre 8, towards the border 6, in *01 mm.; the rows more 
crowded; a circlet of minute apiculi at the border. 
Habitat. — “Barbados, 1865” (Greville!). 
