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Show 276 MR. C H E E S E M A N O N N E W O F I S T H O B R A N C H I A T E S . [Feb. 19, composed of about 22-24 pectinations; foot oblong, thin and flexible, pale waxy white. Shell internal, \ to f inch long, squarish oblong, thin and membranous, semitransparent, slightly iridescent, closely marked with somewhat irregular concentric striae or folds; colour varying from nearly white to pale pinkish or tawny brown. Spire minute, obscure, mouth occupying the whole of the undersurface. M y first specimens of this handsome species were obtained from under stones between tide-marks in Auckland Harbour; where, however, it is by no means common. Near Waiwera and in some other localities on the Hauraki Gulf it is much more frequently met with. It is easily kept alive in an aquarium, but is very sluggish in its movements. 2. PLEUROBRANCHJEA NOV^E-ZEALANDI^E, n. sp. (Plate XV. fig. 3.) Body oval, convex, thick and fleshy, smooth and lubricous to the touch, but the whole surface nevertheless covered with minute puckers and folds. Colour light grey, copiously streaked with irregular anastomosing lines of dark greyish-brown, and sprinkled with numerous minute and almost microscopic white dots. Mantle smooth, not nearly so long as the foot, and not concealing the branchiae, rather broader on the right side; oral veil broad, extending over and concealing the mouth, in front semicircular, and with a delicate fringed margin, but at each side produced into a short tentacle-like lobe ; mouth large, round, in a state of rest concealed in the sulcus between the oral veil and the foot, but capable of being greatly protruded in a proboscidiform manner ; buccal plates two, large, finely and regularly reticulated or faceted; odontophore broad, with numerous rows of similar unciform teeth ; tentacles dorsal, wide apart, short and stout, projecting outwards, folded down the outer side, tips obliquely truncate; eyes minute, black, placed within the integument at the inner bases of the tentacles, quite internal, and not to be seen without dissection ; foot long, extremely flexible, sole pale ashy grey ; branchial plume often over an inch in length, and free for half that distance; pectinations about 17, finely ciliated ; shell none ; length 2*5 to 3*25 inches. This species is very abundant in Auckland Harbour, usually affecting sandy or muddy localities. In the winter and spring months large numbers are often exposed at neap tides, having probably come into shallow water to deposit their ova. Capt. Hutton, of the Otago Museum, informs m e that he has collected the same species at Port Nicholson. It is hardy and not easily killed, and may be kept in confinement for a long time. When in a healthy state it is by no means inactive, crawling along by means of its muscular foot much more quickly than might be expected. It has a curious habit of floating in a reversed position, just under the surface of the water; and I have also observed it swimming by means of rather violent vertical undulations of its body. |
