Greville, on New Diatoms. 
69 
fragment in my own cabinet (half a disc) had, when perfect, 
nine ocelliferous rays. 
Craspedoporus Johnsonianus, n. sp., Grev. — Valve not visi- 
bly cellulate, with five ocelliferous compartments; ocelli or 
pseudo- openings large, transversely oval, close to the margin. 
Diameter -0025''. (Fig. 10.) 
Hab. Barbadoes deposit, from Cambridge estate ; C. John- 
son, Esq. 
In this species the compartments into which the disc is 
divided are more equal, and it consequently bears some 
general resemblance to Actinoptychus (Ehr.). There is, 
nevertheless, a great difference. In both species of our pre- 
sent genus there is a sort of central nucleus, of considerable 
size. No fine, decussating striation is perceptible; and the 
whole structure is quite unlike the hexagonal cellulation of 
Actinoptychus. 
AcTiNODiscus, nov. gen., Grev. 
Frustules free, disciform; valve granulose, with a central 
nucleus and numerous broadly linear rays extending from 
it to the margin. 
This is distinguished from the last genus by the total ab- 
sence of ocelli. The rays are not in the least degree wedge- 
shaped, but are linear, about half the radius in length, and 
resemble the spokes of a wheel. The structure is dense, 
not showing any approach towards cellulation in any part. 
Actinodiscus Barbadensis, n. sp., Grev. (Fig. 11.) 
Hab. Barbadoes deposit, from Cambridge estate, in a slide 
communicated by C. Johnson, Esq. 
The most conspicuous feature in this disc are the numerous 
rays, fifteen in number; they are slightly dilated at the 
ends, and apparently somewhat thickened, but have not the 
slightest indication of an opening. Diameter '0038". 
AuLAComscus. 
Aulacodiscus inflatus, n. sp., Grev. — Disc bullate beneath 
the processes, the buUation causing a dark line of shadow 
just within the margin; processes 4, submarginal, long, 
cylindrical ; furrow defined by parallel lines of granules 
reachmg nearly to the centre, where the granules are arranged 
irregularly round a somewhat quadrate blank space ; lines of 
granules in the spaces between the inflations about 8 in -001". 
Diameter about -0035". (Fig. 12.) 
