[Read before the Wellington Philosophical Society, 9th December, 1882.]

The beautiful little animal described below was collected at Napier by Mr. A. Hamilton, of Petane. Mr. Hamilton kindly forwarded specimens both in glycerine and spirit, so that the bright colourings are to a large extent preserved. I am also indebted to him for notes of colours, etc., taken from living specimens. The accompanying figures of the animal are natural size.

Æolis, Cluv.

Animal ovate; dorsal tentacles smooth, oval, slender; papillæ simple, cylindrical, numerous, depressed, and imbricated; mouth with a horny upper jaw, consisting of two lateral plates united above by a ligament; foot narrow; tongue with a single series of curved, pectinated teeth; spawn of numerous waved coils.

Æolis gracilis, sp. nov.

Body small; tail sharply pointed. Gills as long as greatest width of the body, papillose, crowded, but placed in three tolerably distinct groups on each side of a broad clear line running from the base of the tentacles to the tip of the tail; oral tentacles subulate, rather distant, about twice as long as the greatest width of the animal. Tentacles approximate, about half as long as the oral tentacles. Foot expanded, produced in front, margin thin, slightly puckered.

Colour—body and foot pale pink; tentacles and gills bright red prominently tipped with white.

Length, .9 of an inch.

Hab.—On Ulva, Napier (collected by Mr. A. Hamilton).