PLATE XL. 
Pliocene Pelecypoda and Gasteropoda. 
(Unless otherwise stated, all figures are natural size.) 
Fig. 1. Mya truncata Linne. U.S.N.M. 164950. Left valve; longitude 46 mm. 
Pliocene (Fernando formation), Elsmere Canyon, near Newhall, Los 
Angeles County. Found also in the Recent fauna of the Arctic regions. 
Fig. 2. Trochita filosa Gabb. U.S.N.M. 164949. Slightly imperfect specimen 
viewed from above; maximum diameter 20 mm.; twice natural size. 
Samg locality as fig. 1. Also found in the upper Miocene. 
Fig. 2a. Same specimen as fig. 2. View from the side. 
Fig. 3. Fissuridea marina Carpenter. U.S.N.M. 164945. Specimen viewed from 
above; longitude 14.5 mm.; twice natural size. Lower Pliocene, Third 
street tunnel, Los Angeles. Also found in the Pleistocene and Recent 
fauna of the coast. 
Fig. 3a. Same specimen as fig. 3. View from the side. 
Fig. 4. Cancellaria fernandoensis Arnold. U.S.N.M. 164956. Back view of imperfect 
specimen; altitude 17 mm.; twice natural size. Same locality as fig. 1. A 
similar or identical form was found in the Pliocene of the San Diego well. 
Fig. 5. Tritonium sp. U.S.N.M. 164954. Back view of imperfect specimen; alti¬ 
tude 20 mm.; twice natural size. Same locality as fig. 1. 
Fig. 6. Pisania fortis Carpenter var. angulata Arnold. U.S.N.M. 164959. Aperture 
view of imperfect young; altitude 30 mm. Same locality as fig. 1. A 
rather common species in the Pleistocene and Pliocene of central and 
southern California. 
Fig. 7. Pisania fortis Carpenter var. angulata Arnold. U.S.N.M. 164958. Aperture 
view of imperfect adult; altitude 49 mm. Same locality as fig. 1. 
Fig. 8. Cyprxa fernandoensis Arnold. U.S.N.M. 164961. Type. View from back; 
longitude 40 mm. So far known only from same locality as fig. 1. 
Fig. 8a. Same specimen as fig. 8. Aperture view. 
Fig. 9. Nassa hamlini Arnold. U.S.N.M. 164946. Type. Aperture view of imper¬ 
fect specimen; longitude 15 mm. Same locality as fig. 3. 
Fig. 10. Chrysodomus cf. arnoldi Rivers. U.S.N.M. 164962. Back view of imperfect 
specimen. Same locality as fig. 1. Known also from the Pleistocene 
of San Pedro, Los Angeles County. 
Fig. 11. Priene oregonensis Redfield var(?) angelensis Arnold. U.S.N.M 164975. Back 
view of imperfect and slightly contorted specimen; longitude 71 mm. 
Same locality as fig. 3. Common in the lower Pliocene of the Pacific 
coast. It is the precursor of the Recent Priene oregonensis Redfield. 
Fig. 12. Murex eldridgei Arnold. U.S.N.M 164955. Type. Back view; longitude 
24 mm.; twice natural size. Known only from the same locality as fig. 
1. Near the Recent M. incisa Broderip. 
Fig. 13. Pecten ( Chlamys ) hastatus Sowerby var. strategics Dali. Collection of Delos 
Arnold. Left valve; altitude 36 mm. Pliocene, Santa Barbara. 
Also found in the Pliocene of southern California. 
Fig. 14. Pecten ( Chlamys) bellilamellatus Arnold. Type. Right valve; altitude 18 
mm. Pliocene, Pacific Beach, San Diego. Known only from this 
horizon at this locality. 
252 
