552 
Proceedings of Boyal Society of Edinburgh. [sess. 
Straits, Franz Josefs Land (Grunow); “ Yszee” (Kinker !); Melville 
Bay (Griffin !) ; Los Angelos deposit (O’Meara !). 
C. bisinuatus. Sch., Atl., pi. lxiii. figs. 14, 15. — Diam. from *106 
to *145 mm. Surface showing 2 unsymmetrical depressions, 
convex inwards, close to the border. Central space absent ; rosette 
distinct, composed of few (4 to 6) areolae. Markings polygonal, 4 
in *01 mm., decreasing for a short distance from the rosette, thence 
subequal, and again decreasing near the border ; close to the border 
7 in *01 mm. 
Approaching C. oculus-iridis and C. centralis. 
Habitat. — North Celebes (Grunow, Schmidt). 
C. Weyprerhtii. Grun., Denk. Wien. Ah., 1884, p. 78, pi. iii. (C), 
tig. 8. — Diam. *094 mm. Surface convex. Central space minute, 
rosette small. Markings gradually decreasing outwards ; towards the 
centre 5J, towards the border 7, in *01 mm., each with a distinct 
central dot and minute puncta, 20 in .01 mm. Border broad, of 
two portions, the inner with delicate striae 15 in '01 mm., the 
outer hyaline. 
This species is readily distinguished by its border. 
Habitat. — Franz Josefs Land (Grunow). 
C. undulans, Rattray, C. undulatusf Cstr., Diat. Chall. Exped ., 
p. 159, pi. viii. fig. 3. — Diam. *390 mm. Surface with two con- 
centric elevations — one near the centre, the second close to the 
border. Central space irregular, about of diam. broad. Markings 
polygonal, largest on the elevations, increasing gradually from the 
central space to the inner edge of the inner elevation, decreasing 
suddenly at its outer edge, and again increasing to the inner edge 
of the outer elevation, smallest towards the border, about the semi- 
radius If to 2 in *01 mm. ; rows indistinct upon the elevations, 
secondary oblique decussating rows evident. 
Habitat. — Pacific Ocean, H.M.S. Challenger (Castracane). 
C. convexus. Sch., Atl ., pi. lx. fig. 15. — Diam. T mm. Central 
space absent. Markings hexagonal, distinctly punctate, central 
* Name preoccupied by Cleve ( Kongl . Sv. Vet.- Ale. Handl. StocTch. , 1881, 
No. 5, p. 20). 
