| Marcusia ernesti Hyman, 1953 | Mar, 1940 | | | collected by Ricketts. |
| Euplana pacificola (Plehn, 1896) | Mar 24, 1940 | | | four specimens collected by Ricketts. |
| Alloioplana sandiegensis (Boone, 1929) | Mar 24, 1940 | | | collected by Ricketts. |
| Paraplanocera oligoglena (Schmarda, 1859) | Mar 24, 1940 | | | three specimens collected by Ricketts and mentioned in the "Sea of Cortez" as Stylochus (?) sp. |
| Stylochus sp. Steinbeck & Ricketts, 1941 | Mar-Apr 1940 | | | Representatives taken on the reef at Pt. Marcial, as large thin flatworms with nuchal tentacles. |
| Leptoplana sp. Steinbeck & Ricketts, 1941 | Mar-Apr 1940 | | | One or more additional species, reminiscent of the superficially nondescript genus Leptoplana, were taken at El Mogote, on the reef at Pt. Marcial, and at Port San Carlos, Sonora. |
| Marcusia ernesti Hyman, 1953 | March 1940 | | | "Collected by Ricketts at Point Marcial Reef and Pulmo Reef, Gulf of California" |