542 
Proceedings of Royal Society of Edinburgh. [sess. 
Exped ., taf. iii. fig. 4 ; vi. fig. 13 ; Sch., Atl ., pi. ixiv. fig. 1 ; Grun., 
Denk. Wien. Ak ., 1884, p. 76; Cleve and Moll., Diat ., Nos. 57, 
162, 164; C. radiatus, Bail., Amer. Jour. Sci., 1842, vol. xlii. p. 95, 
pi. ii. fig. 14. 
In all the specimens there is a central space, not indicated in the 
earlier figures. Ralfs first noted the striated border, Janisch the 
more robust character of the markings towards the border, and 
Grunow the delicate puncta on the markings and their small size at 
the border. 
Habitat. — Richmond, Ya. (Ehrenberg, Kinker ! Cleve and 
Moller !) ; Nancoori (Schmidt, Cleve !) ; Sta Monica deposit 
(Weissflog! Grove!); locality 1 (Deby !); Hong Kong (Hardman!); 
Peruvian guano (Cleve ! Hardman !) ; Macabees guano (Firth !) ; 
Crescent City (Hardman !) ; Sea of Java (O’Meara !) ; Maryland 
(O’Meara !) ; Los Angelos deposit (O’Meara !) ; Cove Calvert 
county, Maryland (Greville !); Bay of Bengal (Macrae !); Sta Monica 
deposit, Patagonian guano (Cleve !); Marstrand (Kinker !). 
Yar. pundiformis, nov. C. gigas, var., Grun., ibid., 1884, p. 76. — 
Diam. *151 mm. Markings free towards the centre, from the 
semiradius to the border polygonal, punctiform, almost invisible 
markings at origin of shorter radii. — G. Woodwardii , Eul., var., 
Grun. in Sch., Atl., pi. lxv. fig. 2. 
According to Schmidt, this is intermediate between C. gigas and 
C. diorama, Sch. 
Habitat. — Aegina (Schmidt). 
Yar. diorama. Grun., ibid., 1884, p. 76. C. diorama, Sch., 
Atl., pi. Ixiv. fig. 2. — Diam. 45 to *25 mm. Surface slightly con- 
vex. Markings towards the central space rounded 4 in ’01 mm., 
increasing gradually but to a less degree outwards, subequai — 12^ in 
’01 mm. — on outer half of valve, again decreasing gradually near 
the border. — C. gigas , var. Montereyi , Grun., ibid., 1884, p. 76. 
Grunow’s var. Montereyi differs only in having somewhat 
smaller markings, 3J in ’01 mm. 
Habitat. — Santa Monica deposit (Schmidt, Cleve !); Monterey 
deposit (Grunow, Cleve !); Isle of Muntok, Indian Archipelago 
(Kitton !); Pabillan de Pico guano (Cleve !); Patagonian guano 
(Cleve !). 
