1888-89.] Mr John Rattray on the Genus Coscinodiscus. 575 
Haitat. —Galapagos Islands (Grunow) ; Springfield deposit, 
Barbados (Schmidt) ; Oamaru deposit (Grove ! Kinker !). 
C. armatus. Grev., Trans. Micr. Soc. Lond ., 1861, p. 42, pi. iv. 
fig. 5. — Sometimes obtusely angular. Diam. -0575 mm. Surface 
convex. Central space rounded, about Jg- of diam. broad. Mark- 
ings rounded, granular ; towards the centre 5, towards the border 
8, in *01 mm.; rows straight or curved, radial or subradial, some- 
times forming unequal obscure fasciculi, separated towards the 
border by delicate, clear, slightly elevated lines. Border indistinct. 
— Cosmiodiscus armatus , Scb. (not Grev.), Atl., pi. lvii. fig. 4. 
The delicate elevated lines represent, as noted by Greville, the 
more pronounced ridges of Biddulphia Johnsoni, Ralfs (Traits. 
Micr. Soc. Lond., 1866, p. 4, pi. i. fig. 11). The union of C. 
armatus with the old genus Cestodiscus , as suggested by Habirsbaw, 
is undesirable. 
Habitat. — Barbados deposit (Greville!); Richmond, Va. (Schmidt). 
C. obliquus, Rattray. Cosmiodiscus obliquus, Grev. MS. — Diam. 
*0675 to *075 mm. Surface slightly depressed towards the centre, 
and convex towards the border. Central space small, circular, bear- 
ing a few rounded granules. Markings obtusely angular or suboval, 
with long axis radial, 5-J to 6 near the border, decreasing to 8 in 
•01 mm.; rows radial, towards the border uniformly curved 
towards the same direction, at subregular intervals of about 
•005 mm. short hyaline curved lines on the convex sides of the 
valve, and extending a short distance inwards as attenuating subu- 
late spaces. Border narrow; striae 8 to 10 in ’01 mm. — (PL I. fig. 14.) 
Habitat. — Monterey deposit (Greville !) ; Santa Monica deposit 
(Grove !). 
C. apages* Rattray. Cosmiodiscus normanianus, Grev., Trans. 
Micr. Soc. Lond., 1866, p. 80, pi. viii. fig. 11. — Diam. *045 to ’06 
mm. Surface almost flat. Central space small, indefinite. Markings 
small, round, free granules disposed without order, with wide 
hyaline interspaces between the centre and semiradius; beyond 
this more punctiform, crowded, 8 to 10 in *01 mm.; rows straight; 
distinct radial clear spaces extending from about semiradius to 
* away^s, loose in texture. 
