Description of a new Species of Nitzchia.

[Read before the Philosophical Institute of Canterbury, 1st July, 1880.]

Nitzchia nova-zealandia, sp. nov.

Frustule: front view linear, narrowing at the truncated extremities, opposite side of each end obliquely sloping. Valve: linear on side view and sigmoid, attenuated towards the extremities, and rounded at the ends; one row of puncta round the margin of the valve. Puncta: there are twenty-four puncta or beads to .001 of an inch.

I have been unable to make out any striæ or keel under Beck's 1/10th immersion. The valves of Nitzchia nova-zealandia resemble Homœocladia sigmoidea, but the latter is frondose and the frustules are sigmoidal on the front view, while the former is free and sigmoidal on the side view.