1888 - 89 .] Mr John Rattray on the Genus Coscinodiscus. 633 
clavate rays 6, about *005 mm. broad at their widest part, the faint 
interradial rays about '0025 mm. broad, the compartments reaching 
about of radius from circumference, the areohe subequal, 8 (?) in 
*01 mm. 
Norman provisionally united this species to Asterolamjpra. The 
remarkable appearance of the compartments and rays are sufficient 
to justify its separation as the type of a new genus. 
Habitat . — Sierra Leone (Norman).* 
ASTEROLAMPRA. 
Ehrb. emend., Mon. Ber. Ah., 1844, p. 73. — Circular, rarely 
obtusely and regularly angular. Surface subplain, a central or 
subcentral portion hyaline with distinct rays, the outer portion 
with evident compartments separated by distinct, rarely sub- 
obsolete, hyaline intervals. Colour subhyaline to subpearly or 
pale grey. Central space sometimes distinct, hyaline, granular or 
subareolate ; a rosette rarely differentiated, a central areolate area 
frequent. Markings on central area areolate, rarely arranged in 
concentric zones ; rays diverging from centre or from outer edge of 
areolate area, rarely from an excentric point, straight, arcuate of 
sharply geniculate at or near their middle, frequently dichotomous, 
narrow, more rarely broad or subobsolete, sometimes confined to a 
relatively narrow, submarginal zone ; interradial areas hyaline, or 
with faint diffuse lines passing to centro-lateral angles of compart- 
ments ; compartments with inner ends convex or concave towards 
the centre, sometimes transversely or obliquely truncate, rarely 
asymmetrical with respect to the rays; granular, with irregular, 
wide, hyaline interspaces or areolate, rarely subhyaline or minutely 
punctate ; the areolae in oblique, decussating, substraight rows 
parallel to the edges of the inter-compartmental intervals ; fre- 
quently a single row of larger areolae fringing the compartments ; 
those bounding its inner edge most evident, rarely large and con- 
spicuous ; at each centro-lateral angle a single areola, frequently 
larger and sometimes protuberant into the interradial spaces ; single 
or double granules rarely present at outer ends of intervals. Border 
narrow, hyaline, rarely broad, obtusely angular and subpearly. — 
* Communicated by Mr Frederick Kitton. 
