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Scuta (figs 4a,f) oblong, the basal margin only slightly exceeding half the entire length of the valve; valve strong, rather plainly marked with lines of growth; basal margin at nearly right angles to the occludent margin; tergal margin separated by a slightly-projecting / point from the lateral margin, which in the lower half is slightly protuberant; tergal margin straight, with the edge thickened and slightly reflexed. A distinct, square-edged ridge (therefore formed by two angles) runs from the umbo to the baso-lateral angle, which is itself obliquely truncated. Internally (/), there is a large and deep pit for the adductor scutorum. Terga (fig. 4b) triangular, flat, large, fully one-third longer than the scuta; basal half much produced; basal angle pointed; from it to the apex or umbo there runs a narrow, almost straight furrow, at which the lines of growth converge — it runs at about one-third of the entire width of the tergum (in its broadest part) from the carinal margin. Parallel to the occludent margin, and at a little distance from it, there runs a wide, very shallow depression up to the apex. The scutal margin is not quite straight, about a third part, above a slight bend corresponding with the apex of the upper latera, being slightly hollowed: from the above bend a very faint ridge runs to the apex o f the valve. Upper latera (fig. 4d) large, flat, with five sides, o f which the two upper are much the longest; the basal side is next in length, and the scutal side much the shortest. As far as I can judge of the positions of the lower valves, with respect to the upper latus, I believe, that the rostral latera, probably, abutted against the shortest of the three lower sides; that the carina ran along the one next in length, and the carinal latera along the middle basal side, which I suppose extended in an oblique line, and not parallel to the base of the capitulum: the two upper long sides no doubt touched the scuta and terga. The umbo of growth is at the apex; there is, however, a trace of a projecting ledge

added round the upper margins during the thickening of this upper part of the valve. Two slight ridges run from the apex to the two corners of the middle of the three lower sides. Cannai latera (fig. 4e): these are not quite perfectly seen: the umbo forms a sharp point, whence the valve rapidly expands and curves apparently downwards and towards the upper latera. Near one margin there is a very narrow furrow, and on the other a wide depression, both running and widening from the umbo to the opposite end, which is slightly sinuous. I imagine these carinal latera occupied a nearly triangular space between the middle of the three lower sides of the upper latera and the basal portion of the carina. Rostral latera, rostrum and peduncle unknown; the rostral latera must have been very narrow.