Slide prepared by Emmanuel Samuels.

Actinocyclus Ralfsii is a species of diatom first identified and described by Andrew Pritchard in his book “History of infusoria” in 1861.

Consistently, “E.S.” or Emmanuel Samuels moved to Boston in the mid-1860s. Actinocyclus Ralfsii has since been reclassified as Actinocyclus octonarius var. ralfsii.