. Bulletins of American paleontology. 22 Bulletin 336 of the aulacophore articulating apparatus are not well preserved, but overall appear to differ little from those structures in earlier mitrates. Perhaps the most signif- icant difference between Anomalocystites and older an- omalocystitid genera is the reduction in the number of segments of the proximal aulacophore to only eight or nine (PI. 1, figs. 1-4). Judging from the aulacophore insert area of the theca, the proximal aulacophore was greatly inflated, but had a significant taper toward the styloid (PI. 1, figs. 7, 8). This tetramerous
. Bulletins of American paleontology. 22 Bulletin 336 of the aulacophore articulating apparatus are not well preserved, but overall appear to differ little from those structures in earlier mitrates. Perhaps the most signif- icant difference between Anomalocystites and older an- omalocystitid genera is the reduction in the number of segments of the proximal aulacophore to only eight or nine (PI. 1, figs. 1-4). Judging from the aulacophore insert area of the theca, the proximal aulacophore was greatly inflated, but had a significant taper toward the styloid (PI. 1, figs. 7, 8). This tetramerous structure has sutures in the axial plane and medially along the lateral faces; all sutures abut smoothly, except on the inferior surface where they alternately imbricate to give the structure added flexibility (PI. 1, fig. 3). The styloid, like that of all anomalocystitids, is made up of three segments. So far as can be determined, the styloid blades are not greatly extended as in Enoploura, but are only slightly protuberant, as in Ateleocystites (see Kolata and Jollie, 1982, p. 642). The nature of the. M2 M3 Text-figure 9.—Carapace of Kierocystis insertus. This figure is based on USNM 42166 (PI. 4, figs. 10. 12). The paired plates between the proximal aulacophore and the adorals are the proximal aulacophore insert plates (PSI). For explanations ofplate abbreviations, see Table 1 (foldout inside back cover). Styloid covering plates, the articulation between styloid and distal aulacophore, and the angle of insertion of the distal aulacophore into the styloid, are all un- known. Distal aulacophores are known from only a few spec- imens (PI. 1, figs. 2, 5-9, 14). They are virtually the same as those of earlier anomalocystitids. Several dif- ferences, however, are worth noting. The inferior spines are not as pronounced as in earlier forms and thereby give the inferior faces of the ossicle a more externally- rounded appearance. The covering plates are not as extensively overlapped
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