. Annual report - Western Society of Malacologists. Mollusks; Mollusks. species, resembles Ceroniola Wilckens, 1904, of Maastrichtian age, from Chile. Ceroniola has previously been included in the Mesodesmatidae, but the California species are not mesodesmatids; their hinge is most suggestive of the Donacidae. Only one species, Mesodesma pacifica Hall and Ambrose, 1916, of Miocene age, has been described from California as being a mesodesmatid. It has been reallocated to Myadesma Clark, 1922, a genus of uncertain affinities, but certainly not of the family Mesodesmatidae. Worldwide the family
. Annual report - Western Society of Malacologists. Mollusks; Mollusks. species, resembles Ceroniola Wilckens, 1904, of Maastrichtian age, from Chile. Ceroniola has previously been included in the Mesodesmatidae, but the California species are not mesodesmatids; their hinge is most suggestive of the Donacidae. Only one species, Mesodesma pacifica Hall and Ambrose, 1916, of Miocene age, has been described from California as being a mesodesmatid. It has been reallocated to Myadesma Clark, 1922, a genus of uncertain affinities, but certainly not of the family Mesodesmatidae. Worldwide the family is meagerly represented in the fossil record. Mactropsis Conrad, 1854, from the Eocene of Alabama, although included by most workers in the Mesodesmatidae, is more closely related to the mactrids Spisula and Mulinia, and, as noted above, Ceroniola is probably a donacid. According to the Treatise on Invertebrate Paleontology (Keen, in Moore, 1969), Ervilia, which is reported from the Pleistocene, is the only other fossil mesodesmatid. Three new species from the Late Cretaceous of California have hinges that show evident relationship to Mesodesma and belong to a new mesodesmatid genus. Its hinge has long anterior and short posterior laterals that are striate only on the dorsal side like those of Mesodesma. The new genus differs in having the external ligament on nymphs, and the resilium in a more posterior position, resulting in cardinal teeth that are less crowded. LITERATURE CITED Moore, 1969. Treatise on Invertebrate Paleon. Part N (2): Mollusca 6: Bivalvia. Geol. Soc. PHOTOGRAPH OF MEMBERS, ANNUAL MEETING Row 1: Cynthia Trowbridge, LouEIla Saul, Shi-Kuei Wu, Yvonne Allen, Katherine Stewart. Camilla Wallis. Row 2: Margaret Mulliner, Joyce Genimell, Bei1 Draper, Art Metcalf. Twila Bratcher. Row 3: Judy Terry Smith, Forrest Poorman, Kathy Langan, Helen DuShane, Charlotte Norrid, Nancy Schmidt, Barbara Chaney, Dana Geary, Paul Scott, Michel Montoya. Row 4: Nikki Va
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