and Species of Diatoms from the South Pacific. 183 
flations ; strize coarse, 14 in ‘001", Length :0030". (Plate 
IV. fig. 3.) 
Hab.—Curteis Straits, Queensland. 
This is a very conspicuous member of a little group, the 
frustules of which are distinguished by their constricted or 
sinuated margins. Three species—A. binodis, angularis, 
and lyrata—were discovered and described by my late inde- 
fatigable friend, Professor Gregory, and one, A. Sarniensis, 
was recently added by myself, from a dredging made in 
Guernsey by Dr Wallich. The present is the most robust 
species of the section, and is rectangular in shape, with the 
corners rounded. The whole surface is undulated. 
Amphora flexuosa, n. sp. Grev.—Frustules constricted, 
nearly linear, with truncate produced ends, and six gentle 
undulations having a marginal row of very minute puncta; 
Nodule situated at the angle of the constriction. Length 
0034". (Plate IV. fig. 4.) 
Hab.—Curteis Straits, Queensland. 
A comparison with the following, which has also six un- 
dulations, will show at a glance that our present diatom is a 
genuine species. 
Amphora sinuata, n. sp. Grev.—F rustules narrow, oblong- 
elliptical, with truncate shortly produced ends, and six un- 
dulations, the two middle ones being the largest; nodules 
situated at a distance from the middle sinuation ; strie 
obscure. Length -0028". (Plate IV. fig. 5.) 
Hab.—Curteis Straits, Queensland. 
In the preceding species there is a true constriction, the 
nodule occupying the angle ; in the present one there is no 
proper constriction, but a concave sinuation, the nodule being 
situated apart from it on an inner longitudinal line. 
AMPHIPRORA. 
Ampliprora Thwaitesiana, nu. sp. Grev.—Front view 
somewhat rectangular, broadly truncate at the ends, the 
wings much rounded at the corners and then widely con- 
cave; supplementary wings striate, convex, constricted at 
the nodule, intersecting the primary wings, so as to divide 
the whole length into about three equal parts. Length 
0040". (Plate IV. fig. 9.) 
