Greville,, on New Diatoms. 
103 
Triceratium latum, n. sp._, Grev. — Valve 4-aiigled and cru- 
ciform ; angles very broad^ with nearly parallel sides and 
semicircular ends ; surface with very remote^, scattered puncta^ 
the extreme ends of the angles crowded with minute puncta. 
Distance between the angles -0030''. (Fig. 20.) 
Hab. Singapore ; obtained from shell-cleanings^ by L. 
HardmaU; Esq. 
A striking and distinct species. The puncta are so re- 
motely scattered that but few are situated within the por- 
tions of the valve which constitute the arms of the cross. 
Triceratium quadricorne, n. sp.^ Grev. — SmalL cruciform ; 
lobes somewhat narrowed towards the rounded ends ; surface 
covered with a faint cellulation^ and a punctum in each 
cellule ; a small cluster of minute puncta at the extreme end 
of the angles. Distance between the angles '0016'' (Fig. 
16.) 
Hab. Woodlark Island,, South Pacific ; in a dredging com- 
municated by Dr. Eoberts^ of Sydney. 
The cellulation of the valve is very delicate^ (not hexagonal), 
and the punctum within each cellule minute. There is, in 
addition to the characters already given, a row of small mar- 
ginal puncta, which are most conspicuous in the concavities. 
Triceratium inglorium, n. sp., Grev. — Minute, 4-angled5 
with the angles rounded, the sides slightly concave and faintly 
striated at the margin j centre with a rather large circle of 
subclavate puncta ; extreme ends of the angles with a cluster 
of minute puncta. Distance between the angles 'OOOS'". 
(Pig. 18.) 
Hab. Manilla ; obtained from shell-cleanings, by L. Hard- 
man, Esq. 
I have not been able to perceive any structure in the space 
between the circle of puncta and the margin. 
Triceratium sexangulatum, n. sp., Grev. — Valve with six 
rounded angles, and concave sides; margin rather broad, 
continuous, with a row of puncta in the concave portions; 
surface filled with somewhat crowded circular cellules, which 
become gradually smaller towards the margin, and leave the 
angles smooth. Distance between the angles 'OOIS"'. (Eig. 
24.) 
Hab. Woodlark Island, South Pacific ; in a dredging com- 
municated by Dr. Roberts, of Sydney. 
A fine diatom, beautifully marked Avith circular cellules, 
which pass into small puncta next the margin, and especially 
at the angles, where, however, they stop, leaving a roundish 
blank space, crossed by a shadowy line just within the apex. 
