The Lenticulina (Astacolus) humilis (Reuss, 1863) 'group' and Lenticulina (Astacolus) atherfieldensis (new species) in the Lower Aptian of the the Isle of Wight (U.K.). Cretaceous Research, 4(4) 1983: 349-359. 357 [Zoological Record Volume 120]