By T. W. Kirk.

[Read before the Wellington Philosophical Society, 24th June, 1885.]

Plate IV.

It may be remembered that last year I had the pleasure of exhibiting quite a fleet of “paper nautilus,” and of describing a new species (A. gracilis), for several specimens of which I was indebted to Mr. C. H. Robson, of Portland Island. That gentleman then informed me that he believed there was a third species on the New Zealand coast, but that he had never been able to obtain a perfect specimen. In the “New Zealand Journal of Science” for May, 1884, he mentions having obtained a perfect shell; and in a letter lately received he says: “I told you of a supposed new species of Argonaut, found by me on Portland Island in March, 1884. …I will ask you to examine, describe, and name the specimen which I now forward to you. If it is new, I should like it named after our mutual friend Dr. Buller, who, notwithstanding all he has done for the natural history of New Zealand, has only one bird dedicated to him.… For some time before I obtained the shell which you will receive, I felt sure that a third species visited our shores, having found fragments of shells which did not seem to belong either to A. tuberculata or A. gracilis; but on account of the fragility of the shells in question, the pieces were always too small for practical use, till I obtained the nearly perfect specimen which you will receive, and which you will at a glance perceive is quite distinct from either of the two species above named. I wish to present it to the Colonial Museum, if new, as a type specimen.”

As I have no doubt about its being a new species, I have great pleasure in complying with the discoverer's wish, and naming it after New Zealand's premier ornithologist.

Description.—Shell translucent, sides much compressed, especially towards the keel, giving the aperture a hastate shape; sides with numerous transverse plications, which are not tuber-culiferous, sides project near the spire into wing-like processes, similar to those of A. tuberculata, causing this end of the aperture to look nearly straight. Keels very close together, with small compressed tubercles; colour, white.

Loc.—Portland Island.

This shell is very much thinner, more fragile, and of finer texture even than A. gracilis, and may be distinguished by the general form of the shell, the shape of the aperture, the angle at which the wings spring from the sides, the much narrower space between the keels, and by the plications being true, not