Date 24 April 1786 indicated on title page, but auction did not take place until a month later (Rehder 1967). With a very few exceptions, the work lacks any description (at least in combination with a binominal name) or illustration of species, but many names were made available by indications (a detailed reference list is given on pp. v-vi). Several authorships of the Portland “catalogue”have been discussed, because no author was given on the title page or elsewhere in the catalogue. Humphrey, a famous shell dealer of his time, has been considered a possible author of the “Portland catalogue”, but Solander has been favoured for the authorship of the catalogue for a long time. His name was mentioned in the preface (p. iii) of the work. He was employed to describe and publish the species of the collection of the Duchess of Portland, but died. Nevertheless the authorship was generally attributed to Solander (also by Sherborn) at least of that names with an identifiying “S” because of a note in the list of references that " 'S.' after one or more names refers to a Manuscript Copy of Descriptions of Shells made by the late Dr. Solander, now in the possession of Sir Joseph Banks, Bart., P. R. S." But neither descriptions of Solander were presented in the catalogue nor it is clear from the content of the work that the bibliographical referneces (indications) of the “Solander species” are from Solander himself. Thus Solander cannot be regarded as the author (Art. 50.1.1) also not as “Solander in Lightfoot” (see below). Apart from this Dance (1962) and Kay (1965) pointed out discrepancies of the manuscripts and the “Solander species” of the published work: a number of species were not included in the manuscripts, the references to some species in the Catalogue differed from those in the manuscripts and so on. Malacologists have attributed the work to Reverend John Lightfoot, librarian and chaplain of the Duchess of Portland. His name was not mentioned in the work itself but Dance (1962) presented convincing evidence that he was the anonymous author of the work. That is why Lightfoot's name has been taken for the authorship of the names under Recommendation 51D (under the precondition that the whole work was regarded to have been published anonymously).
