. Bulletins of American paleontology. 36 Bulletin 149 98 or anterior surfaces join mesially under the bifid cardinal process to form an arc of about 60 degrees, which is concave toward the ante- rior. Ihe proximal one-third of the crural plate has its free margin recurved posteriorly to such an extreme degree that it coalesces with the ventro-lateral margin of the chilidium, thus forming a tube, the long axis of which extends laterally and a little anteriorly. The dis- tal portion of the crural plate does not have its free margin as re- curved as the proximal portion, and it forms the internal
. Bulletins of American paleontology. 36 Bulletin 149 98 or anterior surfaces join mesially under the bifid cardinal process to form an arc of about 60 degrees, which is concave toward the ante- rior. Ihe proximal one-third of the crural plate has its free margin recurved posteriorly to such an extreme degree that it coalesces with the ventro-lateral margin of the chilidium, thus forming a tube, the long axis of which extends laterally and a little anteriorly. The dis- tal portion of the crural plate does not have its free margin as re- curved as the proximal portion, and it forms the internal face of a spoon-shaped socket. The extreme distal end of the crural plate is slightly elevated into a sharp ridge, which probably served for at- tachment of the is> Fig. 3. Dorsal cardinalia of Tapajotia taptijotrnsis (Derby). A. Interior view B. Posterior view, c/i, chilidium, , cardinal process, dc, distal portion of the crural plates, niii, median node, rns, median septum, pc, proximal portion of the crural plate, t, tube formed by the coalescing proximal portion of the crural plate and the lateral edge of the chilidium. Drawing by Elizabeth A. Dalve. The cardinal process is a bifid structure lying between the crural plates with its base apparently continuous with them. The lobes of the bifid cardinal process are widely separated, short, strong struc- tures. Between them on the surface of the arc formed by the anterior surfaces of the crural plates is a small, antero-ventrally projecting node. Ihe postero-ventral side of this node is continuous with a plate standing halfway between the two lobes of the cardinal process and joining posteriorly with the internal surface of the chilidium. Thus, there is a median septum between the two lobes of the cardinal pro-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the
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