Introduction
 During the last century, cameral membranes have been reported in many different
 ammonoids (Grandjean, 1910; Schoulga-Nesterenko, 1926, Hölder, 1952, 1954;
 Schindewolf, 1968; Erben and Reid, 1971; Westermann, 1971; Bayer, 1997;
 Kulicki, 1979; Weitschat and Bandel, 1991; Tanabe and Landman, 1996).  Cameral
 membranes include two main varieties: chamber linings coating the inside surfaces
 of each chamber, and three-dimensional structures suspended within the chambers
 (Landman et al., 2006).  In the Mesozoic, cameral membranes have been observed
 in phylloceratids, lytoceratids, and ammonitids.  More recently, similar membranes
 have been observed in Paleozoic prolecanitids (Mapes et al., 2002; Tanabe et al.,
 2005).  Until recently, however, it was unclear whether such membranes occur in
 goniatites (Landman et al., 2006).  Schoulga-Nesterenko (1926) reported mem-
 branes associated with the siphuncle in the Artinskian goniatite Agathiceras
 uralicum (Karpinsky, 1889); however, the illustration of the specimen, which shows
 a central siphuncle, puts its identification as a goniatite in doubt.