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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. Long. 13, Diam. max. 14, apert 3 mill.
A vast majority of its shells are of living species such as Cardium edule, Cyprina islandica, Scalaria groenlandica, and Fusus antiquus, and some few extinct, as Tellina obliqua, and Nucula Cobboldiae.
Arctic shells, which formed so large a proportion in the Chillesford and Aldeby beds, are more rare in the Norwich Crag, though many northern species such as Rhynchonella psittacea, Scalaria Groenlandica, Astarte borealis, Panopaea Norvegia, and others still occur.
What follows will undeceive us: I place separately, in empty cells, a grub of Saperda scalaria and a Volucella grub, both of them white and selected so as not to fill the cell entirely. Their presence is revealed only by the paleness of the hind part which serves as a plug to the opening. A superficial examination would leave the nature of the recluse undecided.
Scalaria rugulosa, G.B. Sowerby. 10. Pyrula, cast of, like P. ventricosa of Sowerby, Tank Cat. 12. Balanus varians, G.B. Sowerby. 13. Scutella, differing from the species from Nuevo Gulf.
A collection of shells, from the island of Quiriquina, has been described by M. d'Orbigny: they are all extinct, and from their generic character, M. d'Orbigny inferred that they were of tertiary origin: they consist of: Scalaria Chilensis, d'Orbigny, "Voyage, Part Pal." 2. Natica Araucana, d'Orbigny, "Voyage, Part Pal." 3. Natica australis, d'Orbigny, "Voyage, Part Pal." 4.
For these beds he has proposed the name of "Thanet Sands," because they are well seen in the Isle of Thanet, in the northern part of Kent, and on the sea-coast between Herne Bay and the Reculvers, where they consist of sands with a few concretionary masses of sandstone, and contain, among other fossils, Pholadomya cuneata, Cyprina morrisii, Corbula longirostris, Scalaria Bowerbankii, etc.
Yet the northern character of the Norwich Crag is not fully shown by simply saying that it contains twelve northern species. It is the predominance of certain genera and species, such as Tellina calcarea, Astarte borealis, Scalaria groenlandica, and Fusus carinatus, which satisfies the mind of a conchologist as to the arctic character of the Norwich Crag.
Prestwich and Searles Wood, senior, who first described these beds, point out that the shells indicate on the whole a colder climate than the Red Crag; two-thirds of them being characteristic of high latitudes. Among these are Cardium Groenlandicum, Leda limatula, Tritonium carinatum, and Scalaria Groenlandica.
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. Aperture oblong, entire, angulated below; peristome incomplete, thin, even-edged.
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