. Bulletin - United States National Museum. Science. A MONOGRAPH OF THE EXISTING CRINOIDS 471. Figure 21.âPeromelra robusta (A. H. Clark), holotype: a, Laterodorsal view of calyx; b, distal half of cirrus; c. Pi, broken but probably of about 13 segments. there is a transition segment about the ninth; tlie division series and first two brachials have well developed synarthrial tubercles and marked lateral flanges; P, is 6 mm. long wdth about 12 elongate, distally flared and spinous, segments; P2 and P3 are pro- gressively shorter; Pa is present. Description.âThe centrodorsal is conical with swo
. Bulletin - United States National Museum. Science. A MONOGRAPH OF THE EXISTING CRINOIDS 471. Figure 21.âPeromelra robusta (A. H. Clark), holotype: a, Laterodorsal view of calyx; b, distal half of cirrus; c. Pi, broken but probably of about 13 segments. there is a transition segment about the ninth; tlie division series and first two brachials have well developed synarthrial tubercles and marked lateral flanges; P, is 6 mm. long wdth about 12 elongate, distally flared and spinous, segments; P2 and P3 are pro- gressively shorter; Pa is present. Description.âThe centrodorsal is conical with swollen sides and a flattened and coarsely papillose dorsal pole, 2 mm. broad at the base and mm. high. The cirrus sockets are arranged in 15 ci'owded and somewhat indistinct columns of usually two each, the sockets of one column alternating with those in the adjacent ones. The cirri are about XXX, 39-47, up to 20 mm. long, rather stout and with the distal portion capable of being tightly coiled. The first segments are broader than long, the length increasing to the eighth to tenth (usually the ninth), which is a transi- tion segment twice as long as broad. The segments following slowly decrease in length so that the outermost are twice as broad as long, or nearly so. The distal dorsal edge of the transition segment is slightly prominent. This feature gradually increases in extent distally, on the last eighteen segments developing into a high thin median dorsal process with a broadly rounded crest arising from nearly or quite the entire dorsal surface of the segments. The opposing spine is long conical, arising fi'om most or all of the dorsal surface of the penultimate segment, its lengtli equal to about half the width of that segment; it is directed slightly distallj'. The terminal claw is about as long as the penultimate segment and is slender and moderately curved. The cin-i are dark in color with a dull surface as far as the middle or outer third of the transition segmen
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Keywords: ., bookauthorun, bookcentury1800, bookdecade1870, booksubjectscience
