Hallo Gary,
thank you - I see Cochlicopa Férussac is the correct date. as well Cionella
Jeffreys 1830, not 1829 (see Kennard & Woodward, 1926: 386).
But to Cochlicopa I find in GITTENBERGER, E., "On Iberian Cochlicopidae and
the genus Cryptazea (Gastropoda, Pulmonata)" - Zoologische Mededelingen,
Leiden, 1983, 57 (23): 301-320 (page 308) a convincing other presentation:

"The use of Cionella Jeffreys, 1830, instead of Cochlicopa Férussac, April
1821, is based on Kennard's (1942: 113) arguing that "Cochlicopa is a
substitute name for Polyphemus Montfort 1810". This cannot be accepted.
Without any doubt, Férussac had a larger species group in mind. As Kennard
(1942: 113) correctly stated. Cochlicopa has been introduced for both "Les
Polyphèmes, Polyphemae, Montf." and "Les Styloides". The fact that the later
taxon is "not defined" (Kennard, 1942: 113), does not mean that it can
simply be neglected; apart from that, the former taxon, sensu Férussac, is
equally obscure. Férussac (April 1821: 28) gave a description for
Cochlicopa, which as such makes the name available. In addition, not a
single species is indicated, but only two taxa of the genus-group mentioned
before, without any bibliographical reference enabling their interpretation.
Consequently, there are no "originally included species [ICZN-Art. 69 (a)
(i)]" in Cochlicopa Férussac, April 1821. There is no article in the ICZN
which demands to violate the obvious intention of the original author in
this case, i.e., to consider Cochlicopa a substitute name for Polyphemus.
The nominal species "first subsequently referred to the genus [ICZN-Art. 69
(a)]" are those mentioned with Cochlicopa by Férussac (May 1821: 54, 55),
among which is C. lubrica. Because earlier type-species selections for
Cochlicopa might be considered invalid, since they do not clearly apply to
the nominal taxon introduced in April 1821. Int. H.W. Waldén and I here
select Cochlicopa lubrica (Müller, 1774) as the type-species of Cochlicopa
Férussac, April 1821. By doing so, this genus name Cochlicopa, widely used
in European literature is saved, the stability in nomenclature is promoted,
and Cionella, once "snatched from the graveyard of synonymy" by Pilsbry
(1948: 1047), with regret, can go back to where it belongs.
The view concerning Cochlicopa presented above, were gained while
corresponding on this matter with Int. H.W. Waldén, who fully agrees with
the final conclusion."
Sincerely,
Gert