Nissen cites two bibliographical references for
Hidalgo, both of which I have not seen:
Rev. r. Acad. Ci. Exact. Fis. Nat. Madrid 21, 1923,
58-120, F.A. Moros;
Journal de Conchyliologie 68, 1924, 170.
Maybe someone who can lay their fingers on these
papers
could comment on their apparent thoroughness.
Scott