XXXIX. Description of a new Estheria from the Carboniferous Limestone of Thornliebank

Abstract

Carapace valves thin, broadly subovate, ¾ inch long, ½ inch high, hinge-line long and straight; umbones only a little in advance of its centre. Anterior border symmetrically rounded; ventral line flatly curved; posterior end deeper than the anterior, obliquely rounded, and meeting the dorsal edge at a strong angle. The surface is undulated by numerous bold concentric wrinkles (like those of some Aviculoid shells), with occasional small irregular parallel wrinkles; and is characterized by close-set minute pittings (fig. 5 a ), spreading all over the surface, but in different states of preservation on different layers and parts of the valves. This very delicate punctation, and the quasi-chitonous appearance of the valves, give these little fossils their claim to be regarded as belonging to Estheria. There are but few Estheria that have the umbones so near the centre of the dorsal border as in these specimens; and I know of none that have the shape and the peculiar punctation of this fine species. This 160-word extract was created in the absence of an abstract