1888-89.] Mr John Rattray on the Genus Coscinodiscus. 
71. 
f A distinct marginal band. Markings granular, 
decreasing slightly outwards, secondary oblique 
69. ■{ rows on marginal band. Apiculi large, inter- 
fasciculate, ....... 
I No such marginal band, ..... 
f Markings actinocycloid, towards centre 8, towards 
border 10, in '01 mm., decussating rows most 
evident towards border. Non-apiculate, 
Markings sub-actinocycloid, towards centre 6, 
towards border subpunctiform 8, in ‘01 mm. 
Apiculi interfasciculate, distinct, some dis- 
tance from border, ..... 
Markings equal, 4 in *01 mm., secondary oblique 
rows straight. Non-apiculate, 
Markings equal, 8 to 10 in '01 mm., secondary 
oblique rows straight. Apiculi interfasci- 
culate, ........ 
Markings 3^ to 4 in ‘01 mm. ; secondary rows 
straight, obvious. Non-apiculate, 
_ Markings robust, increasing to semiradius, 
70. thence decreasing, at centre 4, at semiradius 
3 to 3|, at border 6, in ’01 mm. Central 
papillae evident, 
f Markings punctiform, ..... 
f Markings 15 to 16 in '01 mm., irregular on a 
small round central area, elsewhere in 8 broad 
72. 
proteus. 
71. 
actinosus. 
partitus. 
senarius. 
interlineatus. 
denarius. 
simbirsJcianus. 
72. 
fasciculi. Apiculi interfasciculate, 
glad alis. 
Markings punctiform on a distinct band at 
border, elsewhere 6 in *01 mm. Apiculi pro- 
minent, interfasciculate, 
Markings arranged in striae, at intervals not 
reaching centre. Apiculi distinct in a circlet 
near border. Border broad, .... 
odontophorus. 
marginvlatus. 
Border crenulate, ...... 
crenulatus. 
Border uniformly curved, 
73. 
Fasciculi and rows curved, .... 
74. 
Fasciculi and rows straight, .... 
75. 
Markings areolate, 6 in '01 mm., sometimes non- 
. apiculate, . . . . 
curvatulus. 
Markings rounded, decreasing rapidly outwards. 
Non-apiculate, ...... 
semipennatus. 
Markings 6 to 10 in *01 mm. Apiculi inter- 
fasciculate, 
subtilis. 
Markings 10 in '01 mm. Apiculi prominent. 
Valve minute, ...... 
minutellus. 
73, 
74. 
75. 
fTwo asymmetrical distant processes. Minut 
| apiculi at outer ends of radial clear lines 
13. -J Markings 7 to 8, decreasing outwards to 12, in 
j ‘01 mm., 
I No such processes and apiculi 
f Markings excentric, . 
’ \ Markings non-excentric, 
( Markings irregular on a small excentric area 
77 J Border prominent, ...... 
| Markings similar. A distinct small central 
k nodule. Border simple, 
concmnus. 
76. 
77. 
78. 
africanus. 
vetustissimus. 
