512 
Proceedings of Royal Society of Edinburgh. [sess. 
Atl ., pi. lxii. figs. 16, 17 ; Grun. Denk. Wien. Ak ., 1884, p. 72; H. 
L. Sm., Diat. Spec. Typ ., No. 99 ; Janisch, Gazelle Exped ., taf. 
iv. figs. 10, 11 ; ( 7 . marginatus , var. submarginata, Grun,, ibid ., p. 
72; ( 7 . subvelatus, Grun. — Sell., AiZ., pi. lxv. fig. 9; C. linker - 
ianus , Tru. and Witt, Jeremie Diat., p. 13, pi. iii. fig. 1. 
In a Santa Monica form *13 mm. in diam., discovered by Dr 
Rae, the usual striated border was surrounded by a second more 
sharply defined but narrower band, with a slightly convex surface, 
and bearing delicate striae, 8 to 10 in '01 mm.; at one place this 
band is interrupted and somewhat more convex on the two sides of 
the break. This gives it the appearance of an elastic spring envelop- 
ing the valve. 
Habitat. — Santa Monica deposit (Kinker ! Hardman ! Weissflog ! 
Rae ! Firth !) ; Santa Maria deposit (Rae ! Grove !) ; Santa Marta 
deposit (Doeg !) ; Nagy-Kurtos deposit, Hungary (Rae ! Deby !) ; 
Monterey (Weissflog! Hardman!); Mejillones (O’Meara! Hardman!); 
Jeremie deposit (Truan and Witt); Los Angelos (O’Meara !); Japan 
(H. L. Smith!); Sea of Kamtschatka, 1700 fms. (Bailey!); 
Briinn Tegel (Cleve) ; San Pedro (Grove !). 
Var. kittoniana , nov. — Diam. T125 to *225 mm. Markings 1J 
to If in '01 mm., central papillae prominent, forming transversely 
truncated cones, with finely but evidently and closely furrowed 
sides. 
Habitat. — Holothurians, China (Macrae !). 
Var. fragilis , nov. — Diam. J875 mm. Markings more minute ; at 
the centre 2J, at the border 3, in -01 mm.; adjacent to border a 
single band of markings elongated radially ; central papillae more 
faint, puncta distinct ; oblique decussating rows more evident. 
Habitat. — Santa Maria deposit (Rae !). 
C. implicatus , sp. n. — Diam. T5 to - 25 mm. Surface somewhat 
convex towards the centre. Central space and rosette absent. Mark- 
ings hexagonal, decreasing but very slightly outwards ; at the centre 
3J, towards the border 4J in , 01 mm.; rows irregular, oblique, 
straight or curved, forming short, inconspicuous broad fasciculi, 
that are interrupted by those meeting them at variable angles. 
