Eatoniella delli is a species of marine gastropod mollusc in the family Eatoniellidae. First described by Winston Ponder in 1965, it is endemic to New Zealand, often found in finely divided low tide algae.
In the original description, Ponder described the species as follows:
While the holotype of E. delli measures by , the species shows considerable variation in size, as well as shape and colour. It can be differentiated from E. iredalei due to its shorter spire, larer aperture and weaker varix.
The species was first described by Winston Ponder in 1965, who used the name Eatoniella (Cerostraca) delli. The species is named after Richard Dell, who assisted and advised Ponder during his work exploring the Eatoniellidae family. The modern convention of formatting of the name without a subgenus (as Eatoniella delli) was established by Hamish Spencer and Richard C. Willan in 1995. The holotype of the species was collected by Ponder himself on 21 August 1963, on Corallina red seaweed at Bream Tail, Northland. It is held by the Auckland War Memorial Museum.
The species is endemic to New Zealand, found in the waters of the North Island, South Island, Chatham Islands and the Auckland Islands. The species prefers finely divided low tide algae, including Corallina seaweeds, but can live on large algae and be found under stones.