1888-89.] Mr John Rattray on the Genus Coscinodiscus. 651 
A. Weissflogii. Van Heurck, Syn. Diat. Belg ., pi. cxxvii. fig. 9. — 
Diam. *06 mm. Central space minute, irregular. Markings : rays 
6, straight, robust ; at middle of interradial spaces faint subhyaline 
areas about '0025 mm. broad, extending between central space and 
intervals ; the compartments distinct, extending from -J to of 
radius inwards, their inner ends concave inwards on each side of, but 
protuberant opposite the rays ; delicate, radial, subindefinite, faint 
striae, about *0025 jnm. long fringing their inner edge ; a somewhat 
larger more prominent areola at the centro-lateral angles ; elsewhere 
the markings punctiform, obscure ; the intervals sharply defined, 
tapering slightly towards, but not reaching the border with outer 
ends convex outwards ; a delicate, irregularly sinuate, continuous 
zone of unequal breadth contiguous to the inner ends of the com- 
partments. Border about to of radius broad, its inner edge 
sharply defined, hyaline.- — Pelletan, Les Diat. Nat. Hist ., tom. i. 
p. 206, fig. 112 ; tom. ii. fasc. i. p. 170, fig. 427 ; A. ( pulchra , var.?) 
Weissflogii , Grun. ; Van Heurck, loc. cit. 
In some specimens the outer ends of the intervals between the 
compartments are not swollen, as shown in Professor Van Heurck’s 
figure. 
Habitat. — Barbados deposit (Deby !); Cambridge deposit, Bar- 
bados (Van Heurck). 
Artificial Key . 
fRays straight or subvmiformly curved, springing 
1. -J from a somewhat excentric point, .... 
^No such excen tricky, 
f A large central areolate area ; rays short, numerous, 
2. J compartments convex inwards ; intervals sub- 
j obsolete, ....... 
I No such structure, ....... 
f Compartments obtusely conical, ornamented with 
3. -J distinct subradial dichotomising lines, . 
t No such markings on the compartments, . 
f Rays obsolete or subobsolete or broad ; interradial 
j spaces small, 
j Rays narrow, sublinear ; valve subpearly, 
4. -{ Rays linear ; valve more hyaline, .... 
| Rays broad, subclavate, passing between central 
j Space and intervals between compartments, with 
L inner ends convex to centre, .... 
( Interradial spaces tapering towards centre, 
g j Interradial spaces tapering towards border ; a distinct 
' j round granule adjacent to border opposite outer 
l end of each, 
brightwclliana. 
2 . 
marginata. 
3. 
ralfsiana. 
4. 
5. 
6 . 
7. 
nicobarica. 
8 . 
dubia. 
