458 
Proceedings of Royal Society of Edinburgh. [sess. 
ibid., p. 73, pi. xxvii. fig. 257 ; C oscinodiscus stokesianus forma 
baldjikiana , Grun., ibid., p. 73. 
Distinguished from C. superbus (= Cestodiscus yulcheTlus, Grey.) 
"by its smaller and more crowded markings, and more distant, less 
numerous apiculi. 
Habitat. — Moron deposit (T. G. Stokes, Greville !). 
C. moronensis, Rattray. Cestodiscus moronensis, Grev. MS. — Sub- 
circular. Diam. '075 mm. Central space absent. Markings angular 
towards the centre 8, gradually increasing outwards to 6, at f of 
radius on a distinct hand adjacent to border punctiform, 10 to 12 
in '01 mm.; central papillae small, hut prominent; subulate spaces 
faint, most evident near the marginal band ; rows radial, straight ; 
secondary subconcentric bands well marked within the marginal 
band. Apiculi prominent at intervals of about ‘01 mm. Border 
narrow. — (PI. II. fig. 16.) 
Habitat. — Moron deposit (Johnson !).* 
C.johnsonianus, Rattray. Cestodiscus johnsonianus, Grev., Trans. 
Mic. Soc. Lond., 1865, p. 48, pi. v. fig. 8. — Diam. '08 mm. Central 
space small, indistinct. Markings rounded, granular, 6 in '01 mm., 
smaller and subpunctiform towards the border ; interspaces evident, 
largest opposite origin of shorter rows ; rows radial, straight, most 
crowded towards the border ; apiculi many, stout, spine-like, 
with blunt extremities inserted near border at intervals of about 
*01 to ’015 mm. at the middle of small, rounded, hyaline spaces. 
Border distinctly defined, striae 6 to 8 in ‘01 mm. evident. 
This species forms a transition to Aulacodiscus , from which it is 
distinguished by the absence of primary rays, and the more minute 
and simple character of the processes. 
Habitat. — Moron deposit (Johnson ! Greville). 
C. superbus, Hardman MS. Cestodiscus 'pulchellus (f), Grev., 
Trans. Micr. Soc. Lond., 1866, p. 123, pi. xi. fig. 5. — Diam. -0875 
to T mm. Surface convex towards centre, a distinctly defined 
band adjacent to border. Central space small, indefinite. Markings 
dissimilar on opposite valves of same frustule : on the one rounded, 
pearly, within submarginal band, with distinct hyaline interspaces ; 
* In the collection of Dr Greville. 
