8 APORRHAID GASTROPOD SPECIES FROM THE CRETACEOUS OF THE PACIFIC SLOPE OF NORTH-AMERICA AND CLARIFICATION OF THE TYPE SPECIES OF PERISSOPTERA

Eight aporrhaid species from Pacific Slope deposits of late Early Cret aceous through early Late Cretaceous age are assigned among three gene ra, Aporrhais, Latiala, and Alarimella n. gen. Except for two species of Latiala, Latiala sp. of Albian age from Oregon and Latiala heliaca n, sp. of Cenomanian age from Fresno and Shasta counties, California, the species are of Turonian age. Pacific Slope Latiala was most specie s-diverse during the Turonian and has not been found in younger Pacifi c Slope deposits. The three Turonian Latiala are Latiala californica ( Gabb) from Siskiyou and Shasta counties, California, Latiala sigma n. sp. from the Redding area, Shasta County, and ''Alaria'' nodosa Packar d, 1922, from the the Redding area, Shasta County, and the Santa Ana M ountains, Orange County, California. Aporrhais drachuki n. sp. is from the Santa Ana Mountains, as are two species included in Alarimella n. gen., Alarimella anae n, sp. and the reassigned species, Alarimella v eta (Packard, 1922). Alarimella resembles Rimella of the Strombidae, b ut possesses an expanded outer lip. The total number of Turonian aporr haids known from the Santa Ana Mountains, southern California is incre ased to six species and includes the first record of Aporrhais on the Pacific Coast of North America. Selection of a type species for Periss optera from among Cretaceous species listed by Tate, 1865 ensures that Arrhoges is not supplanted by Perissoptera.