598 
Proceedings of Royal Society of Edinburgh . [sess. 
C. lewisianus. Grey., Trans. Micr. Soc. Lond ., 1866, p. 78, 
pi. viii. figs. 8-10. — Valve elliptical, the sides slightly protuberant 
at ends of minor axis. Major axis ’0875 mm., about 2 to 2f times 
minor. Central space absent. Markings rounded, about 4 in 
•01 mm., largest and irregular around the centre * the rows straight 
and slightly curved along and parallel to the major axis, diverging 
and bent away from the minor ; on a narrow band at the border 
crowded, and forming oblique decussating rows. Border indistinct; 
striae 8 in *01 mm. — Sch., Atl., pi. lxvi. fig. 12 ; Pant., Fossil. Bacil. 
Ung., p. 70, pi. xxv. fig. 232; Cleve and Moll., Diat., No. 162. 
Habitat. — Nancoori (Cleve and Moller ! Cleve ! Kinker ! Hard- 
man !); Maryland (Cleve); Rappahannock, U.S. (Greville !); Rich- 
mond, Va. (Greville !); Szent Peter deposit (Pantocsek); Naparima, 
Trinidad (Firth! Kitton) ; Jones Cliff', Maryland (Marshall!);* 
Trinidad deposit (Greville !) ; Artesian well, Cambridge, Mary- 
land (Doeg !) ; t Monroe Fortress, North America (Weissflog!); 
Monte Gubbio (Grove !) ; Nottingham deposit (Greville!); Los 
Angelos, Cal. (Cambridge !) ; t Calvert County, Maryland (Grove !). 
Var. moronensis, nov. Major axis *0825 mm. about 2~ times 
minor. Central space absent. Markings polygonal, in contact 
3 to 3f in *01 mm., subpearly, the rows arranged as in the type, 
the band at the border sharply defined on its inner side, with 
markings decreasing slightly outwards from 6 to 8 in •01 mm. 
Striated border absent. 
Habitat . — Moron deposit (Hardman !). § 
Var. similis , nov. — Rhombic. Major axis ’05 mm., about If times 
minor. Markings round, granular, almost symmetrical with respect 
to the major and minor axes ; the rows concave towards the former 
on each half of valve ; at the centre about 3i in *01 mm., near the 
border crowded, subpunctiform. — (PI. III. fig. 10.) 
Habitat. — South Naparima, Trinidad (Hardman !). || 
* In the collection of Dr F. W. Griffin. 
t Forwarded by Professor H. L. Smith. According to Dr Griffin, the 
boring also contained Coscinodiscus excavatus var. genuina, and C. excavatus 
var. quadriocellata. 
J In the collection of Dr F. W. Griffin. 
§ In the collection of Dr Greville. 
|| In the collection of Mr Julien Dely. 
