This beautiful shell was dredged in from 8 to 11 fathoms water, on a bottom of sand and shells between Cumberland Island 1.i, and Point Slade (Latitude 21 degrees South Longitude 149 degrees 20 minutes East).
The spiral striae that cross its whorls are grouped in pairs; their interstices are raised, and more or less finely crenulated; as they pass out on the expanded and wing-like varices they diverge, and the lobe-like projections that scallop the margins of the wings are separated from each other by each pair of diverging striae. The fine ribs that cross the whorls are not present on the wings, nor on the back; they are nodulated at their decussation with the raised striae. The wing-like varices of the whorls overlap each other alternately on each side of the shell. The only species to which it has affinity is the R. pulchra.
Scalaria jukesiana. Tab. 3 fig. 7.
Testa lanceolato-turrita, gracilis, alba, laevis, nitida, longitudinaliter costata, costis lamellosis, reflexis, simplicibus, nnmerosis (in ult. anfrac. 20); anfractus 11, tumidi; sutura profunde impressa; varices nulli; apertura orbicularis, margine laevi. Long. 13, Diam. max. 14, apert 3 mill. (Mus. Brit.)
This beautiful little Scalaria is deserving of particular notice on account of the analogy and representation which it exhibits with the S. clathratulus of the seas of the Northern Hemisphere. It is dedicated to the author of the Voyage of the Fly.
New Genus--MACGILLIVRAYIA, Forbes.
Shell spiral, dextral, globular, thin, corneous, transparent (in the only known species smooth or marked by obscure lines of growth) imperforate; spire not produced (with a sinistral nucleus ?). Aperture oblong, entire, angulated below; peristome incomplete, thin, even-edged.
Operculum semicircular, horny, thin, composed of concentric layers with faint traces of a spiral structure at the centro-lateral nucleus, which is on the columellar side; from it there runs a strait rib or process continued nearly to the outer margin, and indicated externally by a depression or groove.
Animal ample, provided with four very long and rather broad linear rugose (or ciliated ?) tentacula; mantle produced into a long siphon; foot very large, expanded, truncate in front, bearing the operculum near its posterior extremity, but not accompanied by filamentous processes or lobes. A float. (Mus. Brit. and Geol.)
This very remarkable mollusk was taken in the towing net off Cape Byron, on the east coast of Australia, in latitude 28 degrees 40 minutes South, fifteen miles from the shore. It was floating and was apparently gregarious. Mr. Macgillivray states that it is furnished with a float in the manner of Ianthina. The largest specimens measure rather less than two lines in diameter. The shell is of a yellow horn colour (as is also the operculum) thin and transparent. It bears a striking resemblance to our much more minute Jeffreysia opalina. The four tentacula and the form of the very peculiar operculum also seem to indicate considerable affinity with the genus Jeffreysia of Alder, and an examination of the remains of the tongue extracted from a dried specimen showed an arrangement and form of the lingual denticles very closely resembling that exhibited by Jeffreysia. On the other hand, the very distinct and long siphonal tube delineated in Mr. Macgillivray's drawing, taken when the animal was alive, would seem to refer this genus to some family probably near to Cancellaridae. It is certainly entirely distinct in every respect from any known Gasteropod. It is a form of very great interest to the geologist, for in it we see the nearest representation of certain palaeozoic (especially Lower Silurian) univalves hitherto referred to Littorina, but which, judging from their associates and the indications afforded by the strata in which they are found, were assuredly either inhabitants of deep water or floaters in a great ocean like the Pacific.