Hello,
look at the work by DAVID G. REID & YIN-MING MAK, "Additions and Corrections
to the Taxonomy of the genus Peasiella Nevill, 1885 (Gastropoda,
Littorinidae)", The Nautilus, 1998, 112 (1): 6-33.
Abstract: Peasiella is a genus of the Littorinidae with minute, trochoidal
shells, found only in the Indo-West-Pacific region. a previous monograph
recognized six Recent species. As a result of new anatomical information
(reproductive anatomy, egg capsules, radulae) two of these are divided into
five and two species, respectively, to make a total of 11 species in the
genus. Three of these are described as new. Additional notes on
distribution, variation and nomenclature are provided on other species.
Characters of the radula and pallial oviduct are relatively uniform
throughout the genus, but penial shapes are often diagnostic. Shell shape
and sculpture show extreme intraspecific variability.
Regards,
Gert
[log in to unmask]