BEECHEY ISLAND, LANCASTER SOUND.

The type specimens of this species were obtained at Cornwallis, Beechey and Griffiths islands. A number of corals in Mr. Low’s collection, from Beechey island, appear to belong to this species, judging from Salter’s description and figures and those of Houghton in the Journal of the Royal Dublin Society, vol. 1, 1856-57 (1858), p. 246, pl. X., figs. 2, 2a.

In Mr. Low’s specimens the inner structure is fairly well shown. The larger septa pass to the centre of the corallites where they are slightly twisted, and together with the arched, rather vesicular tabulÆ, form a definite central area that appears at the bottom of the cups as a more or less distinct boss. The septa (averaging from thirty to forty in number) bear arched carinÆ on their sides. The corallites are slightly larger than those of A. gracilis^† (Billings), from Grand Manitoulin island, Lake Huron (Niagara group), otherwise the specimens could with equal propriety be referred to the Lake Huron species. The size of the corallites varies in A. austini from about 3 to 8 mm. in diameter, in Mr. Low’s specimens up to about 10 mm. across, but in A. gracilis the corallites seldom reach a diameter of 7 mm. If by a direct comparison it is found that Mr. Low’s specimens are without doubt properly referable to A. austini, and if it can be shown that the size of the corallites cannot be relied on as a specific character, then A. gracilis may have to be regarded as identical with A. austini.

Two specimens of corals from Beechey island are not referable to any genus with which the writer is acquainted. In these specimens the structure is revealed, by weathering at the calicular surface and in horizontal and longitudinal sections, as well as in sections obtained by rubbing down and polishing. As the writer is unable to place this coral, to his satisfaction, in any described genus, it is thought best to establish a new genus for its reception. The main generic characters are enumerated below with a brief description of the species which the writer has much pleasure in naming after Mr. Low.

Boreaster. Gen. nov.

Corallum composite, massive (or thickly incrusting), made up of intimately connected polygonal corallites communicating with each other by means of mural pores. Septa in the form of longitudinal lamellÆ, twelve in number. TabulÆ simple.

This genus resembles Favosites in having numerous pores in the walls of the corallites, but differs from it in the possession of lamellar septa somewhat similar to those of Columnaria, Nyctopora and Lyopora. From these three genera, however, Boreaster differs in having 12 septa only, of two alternating sizes, to a corallite. Columnaria and Lyopora are without mural pores. Nyctopora was described by Nicholson as having pores, but in well preserved specimens from the type locality, examined by the writer, mural pores were not seen; it possesses 16 septa of two orders. Boreaster and Calapoecia resemble each other in both having pores, but in the latter genus the corallites are not intimately united under any circumstances, and the septa are in the form of spine-bearing ridges.

This interesting coral may be conveniently grouped, with the FavositidÆ, as its generic affinities appear to place it close to Calapoecia.

Boreaster lowi. Sp. nov.

Corallum growing in irregularly shaped masses with an unevenly undulating surface; composed of small, polygonal corallites so closely united that all trace of the line of contact between contiguous walls is apparently lost. Corallites opening at right angles to the surface, averaging about 75 mm. in diameter and generally five or six sided, as seen in transverse section, the sides of the polygons being distinctly unequal. Walls of corallites thin but less so where they bound the calyces. Septa lamallar, apparently 12 in number, of two sizes, primary and secondary, alternating, the former stout and relatively large, the latter rudimentary and observed with difficulty, especially in the calyces where the six primary septa are paramountly evident, are slightly exsert and apparently connect with the nearest and corresponding ones of contiguous corallites. Pores relatively large, oval, their greater diameter vertical, in a single longitudinal row between each pair of primary septa so as to interrupt the continuity of the secondary septa which are greatly reduced and in transverse sections are only observed in places. TabulÆ not numerous, in the form of simple, flat transverse diaphragms.

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