1888 - 89 .] Mr John Rattray on the Genus Coscinodiscus. 507 
hyaline towards the centre, most evident opposite origin of shorter 
rows; rows fasciculate, straight, those in each fasciculus parallel 
to that at its centre, interfasciculate radial rows evident ; secondary 
oblique decussating rows most evident towards the border. Border 
distinct, striae delicate, 14 to 16 in '01 mm. — (PI. II. fig. 7.) 
Habitat. — Manilla Algae (Grove !). 
C. obnubilus , Rattray. C. umbonatus ,* Cstr., Diat., Cliall. Exped ., 
p. 156, pi. ii. fig. 8. — Diam. '077 mm. Surface rising steeply from 
the centre for about J of radius, thence descending rapidly outwards, 
becoming slightly concave, near the border flat. Central space 
subcircular, about of diameter broad, with several isolated 
granules at its middle. Markings punctiform, subequal, about 
8 in *01 mm., most crowded towards the border ; rows fasciculate, 
those composing each fasciculus parallel to the radial rows at one of 
its sides or subradial ; interspaces small, hyaline, opposite the 
origin of the shorter rows ; apiculi distinct, inserted at the border, 
interfasciculate. Border distinct, narrow. 
Habitat. — Pacific Ocean, 2900 fms., H.M.S. Challenger 
(Castracane). 
§ YI. Radi ati, Grun., Denlc. Wien. Ah., 1884, p. 70; Pant., Fossil. 
Bacil. Ung., p. 69. Pseudostephanodiscus, Grun., ibid., p. 85. 
Clivosi , Pant., ibid., p. 72. Eleganti, Pant., ibid., p. 73. 
Surface flat, rarely undulate, centre sometimes depressed. 
Markings rounded or areolate; rows radial, sometimes faintly 
fasciculate towards the border ; apiculi sometimes present. 
C. diversus. Grun., Denh. Wien. Ah., 1884, p. 72. — Diam. '07 
to '135 mm. Central space absent. Markings rounded, pearly, 
with hyaline interspaces from the centre for \ to f of radius, 
increasing slightly outwards ; on the outer portion polygonal, 2| to 
3, at the border 6 in '01 mm. ; central papillae distinct; secondary 
oblique rows indistinct. Border with inner edge indistinct ; striae 
obvious, radial or subradial, about 6 in '01 mm. — Sch., Atl., pi. lxii. 
figs. 13-15 (without name); C. caraibicus, Tru. and Witt., Jeremie 
Diat., p. 13, pi. ii. fig. 3. 
* Name preoccupied by Gregory for a different species. 
