434 MM. Jones and Kirhby — Carboniferous Ostracoda. 



Beyrichiopsis, gen. nov. 



Carapace- valves outlined and lobed more or less after the fashion 

 of Beyrichia ; either unisulcate, with two roundish separate lobes, or 

 with one subcentral and more pronounced lobe, defined by a faint 

 sulcus on one side and a deeper furrow between it and the swollen 

 posterior part of the valve. The anterior end rather the highest, as 

 in Beyrichia. Two or more thin, curved or sinuous, outstanding 

 ribs pass along the valves (as in some specimens of KirTcbya), one of 

 which is usually placed near the dorsal edge and developed into 

 a crest. The surface is smooth, punctate, or finely granulate. A 

 broad, fimbriate or spinous fringe extends along and a little outside 

 of the free margin of each valve ; this and the ribs form the charac- 

 teristic features of the genus, so far as known. 



1. Beyrichiopsis eimbriata, sp. nov. Plate XL Figs. 3-10, and 

 PL XII. Fig. 5 ? 



Valves ovate-oblong in outline, lobed, bearing two or more longi- 

 tudinal ribs, and with the free margins curiously fringed and spined; 

 height half the length, or less. The dorsal border is straight and 

 nearly three-fourths of the valve's length ; the ventral border is 

 almost straight or slightly incurved ; the extremities are rounded, 

 the anterior being rather the highest. A large globose lobe or boss 

 occupies the posterior third (or more) of the valve ; a much smaller 

 circular or ovate boss is dorsally placed near the anterior third ; 

 and a third, but slighter, swelling is sometimes developed in the 

 ventral region between those already named. A thin lamella-like 

 rib runs parallel and near to the dorsal margin ; a shorter, though 

 similar, rib is usually present along the middle of the posterior lobe ; 

 and a third (more or less sinuous) traverses the ventral region of 

 the valve ; all these ribs run out to nothing anteriorly, and end 

 abruptly posteriorly, often with curved points. At the antero- 

 dorsal angle of each valve, and a little outside of the exact margin, 

 there commences a broad and delicate wing-like fringe, directed 

 slightly outwards, and regularly marked with radiating lines or 

 grooves. This fringe extends round the anterior extremity to beyond 

 the centre of the ventral border, where (the groovings becoming 

 more pronounced) it gradually breaks up into a series of flattened 

 spines that extend, on the same plane, round the posterior extremity 

 as far as the postero-dorsal angle. Seen from above or below, the 

 carapace has a lobate-cuneiform outline, the anterior end being the 

 thinnest, and the posterior almost symmetrically rounded. Surface 

 apparently smooth. Length -gV inch. 



Examples of this species vary very little except in relative height 

 and length. 



The marginal fringe is never perfectly seen in testiferous examples, 

 — as might be expected from its delicate character, the valves having 

 lost it if at all knocked about before imbedment. Many specimens, 

 however, show it more or less imperfectly, so that synthetically a 

 very fair idea of it can be arrived at. At Billow Ness, where this 

 species is abundant on certain planes of the cement-stone before 



