In Panama this species has been collected between Tortola and Tortolita Islands, Panama Bay (USNM E 36137; Centroid Latitude: 8.8639, Centroid Longitude: -79.5619, depth 6 m), from Playa Chumical, Panama Bay (USNM E 51848) and from Saint Elmo Bay, Rey Island, Perlas Archipelago (USNM E 34286), eastern Pacific, North Pacific Ocean.
Mortensen, T. (1948). A monograph of the Echinoidea 4(1). Holectypoida, Cassiduloida. Copenhagen. 371 pp; pages: 210-215.
Kier, P. M. (1962). Revision of the cassiduloid echinoids. Smithsonian Miscellaneous Collections 144 (3), 262 pp.
LSID urn:lsid:marinespecies.org:taxname:513162Cassidulus eugeniae Lovén, 1874 (subjective junior synonym)
Cassidulus pacificus (A. Agassiz, 1863)
Pygorhynchus pacificus A. Agassiz, 1863 (transferred to Rhyncholampas)
Rhynchopygus pacificus (A. Agassiz, 1863) (transferred to Rhyncholampas)
