For a number of years past students have collected shells from Laguna Beach, these and the Bradshaw collection form the basis for this list, which includes shells not farther than ten or twelve miles up and down the coast. The earlier collections were by Mabel Guernsey and P. R. Daggs. Practically all the shells drawn and photographed are from the Bradshaw collection because the shells were in better condition. Some of the earlier specimens were determined by the United States National Museum. Suggestions and corrections were kindly made by Mrs. T. S. Oldroyd. The photographs are by Robins and Cooper. Many of the drawings are by Miss Margaret Cate. Doubtful specimens are largely omitted in this list, but a few are included and marked by a question. Plate I, reduced one-half; Plates II and III, natural size; Plate IV, ×10; Plate V, ×6. BIVALVES _Yoldia cooperi_ Sabb. Fig. 1. _Mytilus californicus_ Conr. Fig. 2. _M. stearnsii_ Pils and Raym. Fig. 3. _Septifer bifurcatus_ Rve. Fig. 4. _Modiolus modiolus_ Linn. Fig. 5. _M. rectus_ Conr. Fig. 6. _Lithophaga plumula_ Hanl. Rock borer. Fig. 7. _Pectin (Chlamys) monotimeris_ Conr. Fig. 8. _Pectin (Chlamys) æquisulcatus_ Cpr. Fig. 9. _Pectin (Chlamys) pastatus_ Sby. Fig. 10. _Pecten (Hinnites) giganteus_ Gray. Fig. 11. _Lima dehiscens_ Conr. Fig. 12. _Ostrea lurida_ Cpr. California oyster. Fig. 13. _Chama Pellucida_ Sby. Fig. 14. _Phacoides californicus_ Conr. Fig. 15. _Phacoides (Lucina california) californicus_ Conr. Fig. 15. _Phacoides nuttallii_ Conr. Fig. 16. _Cardium quadrigenarium_ Conr. Fig. 17. _Cardium (Livocardium) substriatum_ Conr. Fig. 18. _Tivela (Pachydesma) crassatelloides_ Conrad. Fig. 19. small specimen. _Chione fluctifrage_ Sby. Fig. 20. _Chione succincta_ Val. Fig. 21. _Chione undatella_ Sby. Fig. 22. _Donax lævigata_ Desh. Fig. 23. _Tagelus californicus_ Conr. Fig. 24. _Macoma nasuata_ Conr. Bent-nosed Macoma. Fig. 25. _Macoma indentata_ Cpr. Indented Macoma. Fig. 26. _Macoma inflatula_ Dall. Inflated Macoma. Fig. 27. _Samele rupium_ Sby. Semele-of-the-Rocks. Fig. 28. _Cumingia californica_ Conr. California Cuming-shell. Fig. 29. _Mya (Cryptomya) californica_ Conr. False Mya. Fig. 30. _Spisula planulata_ Conr. Fig. 31. _Spisula falcata_ Sld. (?). Falcate Mactra. Fig. 32. _Paphia staminea_ Conrad. Ribbed Carpet-shell. Fig. 33. _Paphia tenessima_ Cpr. Finest Carpet-shell. Fig. 34. _Parapholas californica_ Conr. California Piddock. Fig. 35. _Pholadidea penita_ Conr. Common Piddock. Fig. 36. _Pholadidea subrostrata_ Sby. Little Borer. Fig. 37. _Milneria minima_ Dall. Last Milner-shell. Fig. 38. _Aula (Nucula) casternsis_ Hinds. Camp Nut-shell. Fig. 39. FRESH-WATER AND LAND SHELLS UNIVALVES _Physa heterostropha_ Say. Laguna stream. Fig. 40. _Physa occidentalis_ Tryon. Aliso Lake. Fig. 41. _Limnophysa palustris_ Mull. Fig. 42. _Planorbis (Helisoma) trivolvis_ Say. Fig. 43. _Helix aspera_ Mull. Fig. 44. _Epiphragmophora_ Sp. Fig. 45.