Dear Kay;-
        Your dates for the Sowerby boys are correct. We published a small piece
on them in the Dec. 96 issue of EPINET. Their on-going work (The
Thesaurus Conchyliorum) was published in five volumes.
        C. Davies Sherborn published, in 1894, On the Dates of Sowerby's
Genera of Recent and Fossil Shells. It was in "Ann. Mag. Nat. Hist,6th
ser.,vol 13, pp 370-371.
        There were also other Sowerby brothers. I have heard from two of their
decendents in the past. One lives in NZ and another in (I believe)
Rockville, MD.
        Check Dec. 1965 HSN for an article by Katherine V.W. Palmer.
        Hope this helps.
        K. Palmer stated that "---during certain periods, genera and species
were described by at least three Sowerbys at the same time in different
publications.
        Art