2-1 
GiiEv iLLE^ on New Diutoitis. 
the ease in A. Macraeanus, there is no part iiucovered by 
these apiculi^ except the roundisli intervals between the 
process-bearing spaces, and they are particularly numerous, 
as will be seen by referring to the figure, all round the 
margin. 
In the above remarks I have referred only to A. Peter sii 
as occurring in South Africa. Australian specimens I have 
never seen, but through the kindness of Professor Walker- 
Arnott I possess a disc of the so-called New Zealand variety 
of which Mr. Kalfs remarks (a^ritch. Infus.,' p. 843) that 
specimens from that quarter " have the granules and mark- 
ings more distinct and the inflations smaller, less definite, 
and further from the margin.^^ It unfortunately happens that 
the disc in question has the concave surface uppermost, so that 
I cannot obtain a clear view of the processes. Their position, 
however, agrees with my proposed new species, so does the 
margin ; and the surface, as far as I can see it, is covered 
with raised points, as iu my Ceylon specimens. I gladly 
appropriate Dr. Macrae's name to this diatom, as, perhaps, 
the finest and uiost interesting thing in the collection he has 
kindly placed in my cabinet. 
AulacocUsms Jonesianus, n. sp., Grev. — Disc very large, 
somewhat lurid, with minute radifiting granules, and a 
marginal belt of minute scattered apicuii ; processes small, 
oblong, submarginal, the connecting furrows inconspicuous. 
Diameter -01 lO". (PL II, fig. 5.) 
Hab. Guano ; locality unknown ; Dr. Macrae. 
A very fine and large species. The surface is filled up 
with minute granules, which at first sight seem all equal in 
size, but on a careful inspection are found to diminish 
insensil)ly towards tiie circumference. At the margin they 
l3ecome rapidly smaller, being about 15 in 'OOl/'. There is 
110 perceptible umbilicus, and the furrows are so inconspicuous 
that they are scarcely to be perceived, except by commencing 
at the processes and directing the eye along the two series 
of granules of which they are composed. Near the processes 
the two series of granules slightly diverge, and then leave a 
small, subtriangular, hyaline space. The processes are situ- 
ated at less than their own length from the margin. Minute 
apicuii, similar to those which occur in A. Peter sii and 
scaher, are in this species confined to a marginal space equal 
to about a fourth of the radius. 
I have much pleasure in dedicating this noble diatom to 
Professor Jones, of the Calcutta University, who is asso- 
ciated with Dr. Macrae in the investigation of Indian Diatom- 
aceae. 
