Intracapsular development in the freshwater gastropod Chilina dombeiana (Bruguiere, 1789) (Gastropoda: Hygrophila: Chilinidae)

Chilina dombeiana (Bruguiere, 1789) is a native Chilean species inhabiting freshwater and estuarine environments. In the present study a series of stages for embryonic development of the embryo is described. The snails lay gelatinous and transparent zig-zag-like string egg masses, ranging between 10 and 130 mm in length. Each egg mass contains a variable number of embryos ranging from 60 to 298 eggs with a mean density of 2.9 times mm super(-2) (+ or - 0.7 SD). Embryos inside egg masses are individually encapsulated and embedded in a jelly matrix. Hatching as crawling juveniles took place after 28 days, indicating that direct development occurs in this species. In contrast to other freshwater pulmonates, the well-developed operculum observed in C. dombeiana from the veliger stage, suggest a marine ancestry for this species.