1888-89.] Mr John Rattray on the Genus Coscinodiscus. 
611 
f Markings minute, rows radial. Surface convex, 
Markings punctiform, interspaces large ; rows 
radial, faint, ....... 
Markings minute, granular, equal, 9 to 10 in 
•01 mm. ; rows radial, crowded, 
Markings punctiform, irregular, and with hyaline 
2 g ! interspaces for § of radius, on outer third more 
' ' minute, forming radiating striae. Non-apicu- 
late, . ' 
Markings rounded, granular, irregular for § of 
radius, on outer third forming evident striae. 
Apiculi 8, large, at outer edge of central 
portion, ....... 
.No such arrangement of markings, . 
f On a small central area the markings large, un- 
j equal, beyond this much smaller, 2| in ’01 mm. , 
j increasing gradually outwards to about § of 
j radius, thence decreasing ; irregular on the 
j central area, beyond it in radial rows. 
I No such central area, ..... 
28. 
Five to 8 narrow hyaline lines radiating around 
centre, expanding outwards, and terminating 
at semiradius, ...... 
No such hyaline areas, ..... 
Markings irregular, . 
Markings in more definite order, 
30. 
Markings punctiform, 
Markings rounded, granular, 
Markings angular, 
r Interspaces wide, a circlet of long, narrow, curved 
apiculi inserted some distance from border, 
Interspaces unequal, largest either towards centre 
or towards border. Valves dissimilar, . 
Interspaces subobsolete, markings crowded. 
32. -j Apiculi minute, scattered over surface at wide 
intervals, ....... 
I Interspaces minute ; markings largest, most 
crowded and most evident at centre ; apiculi 
j . at border only, minute. Border broad, sharply 
L defined, strise 17 to 18 in '01 mm., 
f Markings somewhat smaller towards border ; 
interspaces largest towards centre. Border 
distinctly hyaline, ..... 
Markings small, more crowded towards centre. 
33. Border prominent, ..... 
Markings subpearly, rounded, robust. Inter- 
spaces wide, ....... 
Markings large, round, still more robust. Border 
L broad, not sharply defined, with coarse strise, . 
f Markings 4 to 5 in ’01 mm., smaller towards 
border ; a circlet of irregular apiculi at border, 
I Markings large and irregular, on a band adjacent 
34. «{ to border, and at irregular intervals elsewhere. 
A circlet of large radial subregular areolae 
1 forming the border, . . ... 
I No such markings, 
cervinus. 
confertus. 
granulatus. 
Hauckii. 
hirtulus. 
27. 
megacentrum. 
28. 
pulcherrimus. 
29. 
30. 
31. 
32. 
33. 
34. 
insutus. 
dimorphus. 
impolitus. 
granulosus. 
exasperans. 
cinctus. 
nitidus. 
subnitidus. 
antediluvianus. 
luxuriosus. 
35. 
