Notes on East African Land and Freshwater Snails. 8. The rediscovery of Trochozonites (Zonitotrochus) adoxa Connolly (Gastropoda, Helicarionidae)

CONNOLLY (Ann. Mag. Nat. Hist (9), vol. 15, p. 459 (1925)) (as adoxus) described this species from a shell collected by the botanist R. A. DUMMER at Malange, Abiri Forest (? Mabira Forest). The type was stated to be in the South African Museum but when Dr. K. H. BARNARD looked through the collections he could find nothing labelled with CONNOLLY’S name. Looking through the shells collected by DUMMER, however, he found, apart from specimens of Trochozonites suturalis d’A illy and T. adansoniae (Morel.), a specimen of a third unnamed species which matched the dimensions and description of T. adoxa. CONNOLLY presumably returned the shell before he had decided on a name, or even to describe it at all, because the South African Museum received the shells several years before CONNOLLY’S description was published. Dr. BARNARD kindly lent me this shell, which I wished to compare with another single specimen of a Trochozonites collected several years ago in evergreen forest near Kampala by Dr. E. PINHEY. I had been carrying this specimen around with me, comparing it with as many types in European museums as possible, but had never succeeded in naming it. It proved, however, to be identical with T. adoxa Connolly and is thus the second specimen to be reported. It differs quite clearly from the other species of the genus by having a spire with distinctly convex sides, a very pronounced and pinched keel and broadly spaced ribs. T. sharpei Smith described from Central Africa is smaller, more conical and has a different sculpture; T. leptalea Smith, which has a sculpture similar to that of T. adoxa, has markedly concave sides to the spire which has a projecting apex. The four species described by PRESTON in 1914 all differ in details of size and sculpture, as also do those described by PILSBRY in 1919. Dr. PINHEY’S specimen has been deposited it the Coryndon Museum, Nairobi. The following key and the figures in plates 1 and 2 will separate the species I have been able to examine from East Africa. I have included a Sitala species which might easily be assigned to the wrong genus.