GENITAL MORPHOLOGY OF CARACOLLINA-LENTICULA (MICHAUD, 1831), WITH A NEW PROPOSAL OF CLASSIFICATION OF HELICODONTOID GENERA (PULMONATA, HYGROMIOIDEA)

The genital system of Caracollina lenticula (Michaud, 1831) has been s tudied in many Iberian populations, revealing a high morphological div ersity affecting mainly the stimulatory apparatus. The general pattern (mucous gland plus ''appendix'' plus dart sac) appears sometimes modi fied due to the absence of the ''appendix'' or the mucous gland, or ev en both of them simultaneously; whenever the ''appendix'' is absent, t he dart sac is also lacking. Observations carried out in serial sectio ns show that the mucous gland is attached to the ''appendix'' and that the so called ''appendix'' is an organ where secretion elaborated by the mucous gland is accumulated, thus corresponding to the accessory s ac in the sense of Nordsieck (1987). Caracollina lenticula was placed in the Helicodontinae by Hesse (1918). In this paper, a critical revie w of the classifications of the Helicodontinae (Nordsieck, 1987, Schil eyko, 1991) is made. We agree with Nordsieck in considering the Helico dontinae to be a polyphyletic assemblage of genera and thus an artific ial group, but there are two main points of discordance: Ciliella is r elated to Hygromiinae (Hygromiidae) on the basis of its anatomy and sh ell microsculpture, which implies a nomenclatorial change for the Nord sieck's ''Ciliellinae, '' once Ciliella is excluded. Moreover, all gen era of this group, including Caracollina and Oestophora (which were er roneously considered devoid of accessory sac), have a dart sac with ac cessory sac and mucous gland (except secondary losses) and, therefore, a subdivision based on the stimulatory apparatus alone is unjustified . Consequently, Schileyko's classification of this group in four subfa milies is also rejected. We propose the division of the ''Helicodontin ae'' into two unrelated families, Helicodontidae and Trissexodontidae. The inclusion of Helicodontidae in the superfamily Hygromioidae is un clear, because it has a penial caecum and lacks a penial papilla, wher eas Trissexodontidae is considered a primitive taxon of Hygromioidea, and the general pattern of its stimulatory apparatus next to the plesi omorphic condition of Hygromioidea.