Hyolithes endoi was named by Howell (1946) [COMMENTS: Poor preservation of type specimens for this species renders it's diagnosis incomplete and it's generic identifications doubtful. TYPE SPECIMEN: = lectotype. TAPHONOMY: That specimen preserves the original shell, but only the venter is exposed. The dorsum is concealed by matrix, and any attempt to free it might cause the specimen to shatter. The shell is broken to expose a small portion of the internal mold near the apertural end, but enough shell is preserved for lirae to furnish details of the ligula.]. Its type specimen is USNM 57815-A, a shell, and it is a 3D body fossil.