1888-89.] Mr John Rattray on the Genus Coscinodiscus. 619 
Markings punctiform, on inner half of valve in 
faint radial rows on outer half forming striae 
14 in '01 mm., at subregular intervals straight 
hyaline radial lines, most prominent at their 
outer ends, ....... 
Markings faint, minute, granular, most loosely 
disposed towards centre, at semiradius 6 in 
*01 mm., towards border punctiform in radial 
strise, 8 to 10 in ’01 mm., between the striae at 
subregular intervals indistinct short hyaline 
spaces, ........ 
I Appearance otherwise, ..... 
'Outline hexagonal. Markings round, granular, 
about 15 in *01 mm. , rows radial or somewhat 
oblique, 
Outline polygonal, ...... 
Outline diamond-shaped. Markings rounded 
and granular towards middle of large central 
84. -J area ; on a distinct zone adjacent to border 
subpunctiform, 10 in ’01 mm. ; rows radial, 
apiculi distinct, ...... 
Outline elliptical or diamond-shaped. Markings 
rounded. 6 to 8 in *01 mm. ; rows radial, oblique 
| decussating rows at border ; interspaces hyaline, 
l Outline circular, ...... 
f Central space excentric. Markings punctiform 
j in distant rows, on a band around central space 
| larger, .... .... 
85. 4 Central space slightly excentric. Markings 
round, granular, 5 in ‘01 mm. , rows fasciculate, 
those in each fasciculus parallel to central row, 
L Central space non-excentric, .... 
r Central space extending to § radius, hyaline. 
Markings punctiform ; rows close, radial, 
Central space extending almost to semiradius. 
Markings polygonal, delicate, increasing 
slightly outwards ; rows radial, 
Central space extending to -J radius, sharply 
defined. Markings punctiform, 28 in ’01 mm., 
86. ■{ forming radial striae, ..... 
Central space large, not smooth. Markings 15 
in ‘01 mm., . . . . 
Central space large (‘0375 mm. broad), at its 
centre a group of irregular apiculi, at its edge 
a circlet of similar apiculi at wide intervals. 
Markings 6 to 7 in ‘01 mm., .... 
L Central space otherwise, ..... 
( Radial plications from centre to border, produc- 
87. -J ing a wheel-like aspect, ..... 
[ No such plications, 
( Markings non -fasciculate, 
88. -J Markings obscurely fasciculate, .... 
( Markings obviously fasciculate, .... 
( Surface with a distinct central portion extending 
I to about f- radius, and with its outer edge 
] crenulate, sharp, ...... 
I No such crenulate portion, .... 
perikompsos. 
tenuis. 
84. 
flaqrans. 
polygonus. 
rhombicus. 
punctatus. 
85. 
rotula. 
inclusus. 
86 . 
vacuus. 
liocentrum. 
mesoleius. 
disciger. 
Gazelles. 
87. 
trochiscos. 
88 . 
89. 
90. 
91. 
Trinitatis. 
92. 
