592 Proceedings of Royal Society of Edinburgh. [sess. 
— Diam. *048 to ’0625 mm. Surface almost flat. Central space 
small, bearing a few isolated granules. Markings punctiform, 15 
in -01 mm.; rows straight, most evident on outer § of valve; 
apiculi distinct, at intervals of about *005 mm., forming a circlet a 
short distance from border. Border narrow, hyaline. 
Pantocsek places this species amongst the Fasciculate but in his 
type the rows are radial and straight, so that it belongs rather to 
the Radiati. 
Habitat.— -Elesd marl (Pantocsek !). 
C. patera. Cstr., Diat. Chall. Erped., p. 155, pi. ii. fig. 6. — 
Diam. *0575 to *089 mm. Surface hat-shaped, centre slightly 
depressed, thence rising slightly for about of radius to form a 
distinct circular ridge, whence it descends more rapidly, becoming 
almost flat near the border. Central space irregularly rounded, 
tV k° iV diam. broad, bearing a few isolated granules. Markings 
punctiform, subequal, but becoming more crowded and sometimes 
slightly smaller towards the border; towards the centre 8 to 10, 
towards the border 10, in *01 mm.; rows irregularly and faintly 
fasciculate, sometimes at unequal intervals, stopping short of the 
border ; interspaces hyaline. Border narrow, hyaline. 
Distinguished from C. umbonatus, Cstr. (non Greg.) by the 
arrangement of the markings and the absence of apiculi. 
Habitat. — Pacific Ocean, 2900 fathoms, H.M.S. Challenger 
(Castracane) ; Gazelle Expedition (Weissflog !) ; Szent Peter deposit 
(Pantocsek) ; Barbados deposit (Johnson !). 
C. densus. Grove and Sturt MS. — Diam. *0575 mm. Central 
space distinct, irregularly rounded, about of diam. broad. 
Markings closely disposed, rounded, granular, 6 in *01 mm., sub- 
equal for about f of radius, somewhat smaller towards the border ; 
radial rows obscure ; short, secondary, transverse or slightly oblique, 
somewhat flexuous rows more evident, non-decussating for about 
f of radius, beyond this to the border decussating, but more faint. 
—(PI. II. fig. 9.) 
Beadily distinguished by the subopaque appearance and short 
secondary rows. 
Habitat. — Oamaru deposit (Kinker !). 
