34 Dr George Lawson on Lemania variegata of Agardh. 
may be found, on investigation, to be well-marked species. 
The various forms deserve a careful examination, and I would 
beg to direct the attention of British botanists to the subject. 
Descriptions of New Genera and Species of Diatoms from the 
South Pacific. By R. K. Grevitie, LL.D., F.R.S.E., &.* 
(Plate I). 
The diatoms described in the present communication 
were all obtained from dredgings made on various coasts in 
the South Pacific, and kindly placed in my hands by my 
obliging correspondent Dr Roberts of Syduey. Many other 
novelties, of equal interest, contained in these dredgings, 
will (D.V.) form the subject of future papers. 
STICTODESMIS, nov. gen., Grev. 
Frustules elongated (sessile?), in front view linear, rec- 
tangular, with two conspicuous rows of puncta disposed in 
pairs ; side view linear, with terminal and central nodules, 
median line, and numerous transverse pervious septa. 
It is difficult to indicate the systematic position of this 
curious diatom. The transverse septa, as shown in the 
lateral view, and very elongated form, are suggestive of 
some affinity with Climacosphenia : but from that genus 
and the other, Licmophore, it differs in the linearity of the 
frustules, and in the presence of nodules and a median line, 
as well as in the different nature of the septa themselves. 
With the Fragillarie it might be compared in its pervious 
septa, conjoined with the similarity of both ends of the 
frustule ; but Stictodesmis is not compressed in the lateral 
view; and here also the median line and nodule, and 
position of the septa, indicate a different structure and 
different relations. The genus, in fact, cannot be referred 
to any of the families as at present constituted. 
Stictodesmis australis, n. sp., Grev.—(Pl. I. figs. 1-4). 
Hab. Harvey Bay, Queensland, and at Port of France, New 
Caledonia ; in dredgings communicated by Dr Roberts of 
Sydney. 
* Read before the Botanical Society of Edinburgh, 14th May 1863, 
