Pedro Romero sent me a link to a recent paper on Neotropical snail morphology, of which he one of the co-authors.
The paper is on the morphology of the foot in different genera of land snails from Peru, and its evolutionary relevance. Although the paper is in Spanish, there is an abstract in English:
We describe the anatomy of pediose gland in five species of Megalobulimus (Megalobulimidae) and contrast them with those of succineid, orthalicid and helicid gastropods. The presence of a membrane that isolates the pediose gland from the visceral cavity is a synapomorhy of the Stylommatophora clade. A variable range of fixation of the gland to the muscular foot is observed in studied species, from a gland barely held by few fibers (Megalobulimus) to a totally isolated gland (Cantareus), passing through different intermediate grades (Succinea and Bostryx). The pediose gland in Heterovaginina limayana (Systelomatophora) is not attached to the bottom of the visceral cavity. The glandular portion is a voluminous structure that dangles from the capsule roof in Mega- lobulimus, whereas in other species it is attached to the capsule internal wall. We describe new pediose gland characteristics that reinforce diagnosis of the genus Megalobulimus and provide more phylogenetic information.
Borda, V., Ram??rez, R. & Romero, P., 2010. Glandula pediosa de moluscos terrestres y sus implicancias evolutivas, con ??nfasis en Megalobulimus. – Revista peruana de Biologia 17: 43-52.