Dates according to Winckworth, R. 1942. A note on Rang, Leuckart and Ehrenberg. Proceedings of the Malacological Society of London
, 24: 290.
Pages 1-22 are reviewed in Isis
, 22: 1291 and there dated 1828. The complete book is reviewed, without mention of being published in parts, in Bulletin des sciences naturelles et de géologie
23(10) of October, 1830. Some footnotes in the text are from Rüppell, others from Leuckart, but there is no reason to question a joint authorship of the whole paper.