V. On some Estheriæ and Estheria -like Shells from the Carboniferous Shales of Western Scotland

Abstract

Some years ago my friend Mr. John Young, F.G.S., drew my attention to some Estheria -like shells from the neighbourhood of Glasgow, and one of them in particular seemed to me at the time to present features sufficiently characteristic to allow of its being referred to that genus of bivalved Crustacea. Since then both Mr. Young and myself have examined it and its associates again and again; and I have come to the conclusion that its form is that of a Posidonomya , and that its punctate ornament can be matched among Molluscan shells. Hence it has to be removed from the Crustacean genus, and is treated of further on at page 83 as Posidonomya punctatella , Jones. Among the Carboniferous specimens, however, that have come under our notice are other little Estheria -like fossils, and of these I offer the following descriptions, with figures very carefully executed by Mr. George West, who illustrated my “Monograph of Fossil Estheriœ ” Palaeontographical Society, 1863. The plate has been drawn with aid of a grant from the British Association for the illustration of Palaeozoic Phyllopoda. 1. Estheria Youngii, sp. nov. (Plate V., figs, 1 a , 1 b .) This well-preserved right valve, retaining its outline and nearly full convexity, is sub-triangularly ovate, being straight above on the back or hinge-line, elliptically and obliquely curved below, obliquely rounded in front, and contracted and somewhat obliquely truncate behind. It is 8·5 mm. long, 4·5 mm. broad at its greatest height—that is below the umbo, and at one-fifth of the length of the This 250-word extract was created in the absence of an abstract