452 Proceedings of Royal Society of Edinburgh. [sess. 
C. inexpedatus , sp. n. Coscinodiscus (?) sp. (?), Cstr., Diat. Chall. 
Exped ., p. 163, pi. x. fig. 10. — Elliptical; major axis *143 mm. 
about 1J times minor. Central space absent. Markings rounded, 
granular, 4 to 5 in *01 mm. A distinct hyaline band adjacent to 
the border, about ^ of major axis broad, its inner edge somewhat 
irregular. Border narrow, hyaline. 
This species forms the transition to the genus Willemoesia, Cstr. 
(ibid., p. 165, pi. viii. fig. 8), which is not sufficiently distinct from 
Coscinodiscus to be separated from it. 
Habitat. — Zebu, Philippine Islands (Rae). 
C. tenuisculptus , sp. n. Stoscliia ? punctata , Grove and Sturt, 
Journ. Quek. Micr. Cl., 1887, p. 145, pi. xiv. fig. 52. — Elongately 
elliptical, the sides subuniformly curved, or with evident local 
constrictions ; length, *1375 mm., about 7 times the greatest 
breadth ; surface slightly convex. Central space absent. Markings 
small, free round brilliant granules, with, wide hyaline unequal 
interspaces disposed subuniformly over the general surface. Border 
narrow, but sharply defined. 
Habitat. — Oamaru (Grove !). 
C. humilis, sp. n. Willemoesia sp., Cstr., Diat. Chall. Exped., 
1886, p. 165, pi. viii. figs. 8, 8a, 8b. — Elongately elliptical; the sides 
slightly concave to convex ; extremities unequally obtuse ; length 
*0625 to 425 mm., from 7 to 11 times greatest breadth. Surface 
slightly convex. Central space absent. Markings small, round, 
granular, most crowded towards the border, sometimes leaving an 
irregular elongate hyaline area at the middle, or punctiform and 
closely arranged. Border narrow, hyaline. 
Distinguished from C. tenuisculptus. by the general appearance 
and arrangement of the markings. 
Habitat. — (?) (Castracane). 
C. cinctus, Klitz. Bacil., p. 131, pi. i. fig. 17. — Diam. ’0835 mm. 
Surface flat towards the centre, convex near the border. Central 
space absent. Markings round, granular, crowded towards the 
centre; elsewhere remote, scattered. Border distinctly defined, 
striae interrupted at the middle. — Ralfs, in Pritch. Inf., p. 831; 
