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Table 1 Timing of developmental stages of Gibbula varia (at 22°C); different stages of larval development and metamorphosis of G. varia inside the gelatinous egg capsules before hatching.

From: Conservation of ParaHox genes' function in patterning of the digestive tract of the marine gastropod Gibbula varia

Name of stage and approximate time of development (hpf) Brief description of main features
Early Trochophore Larva (12 hpf) The pretrochal cells are smaller than the posttrochal cells; prototroch starts to form by cilliation of trochoblasts; shell gland starts to evaginate; foot rudiment and stomodaeum are not completely formed.
Late Trochophore Larva (18-24 hpf) The larva comprises a prototroch, shell field surrounded by mantle edge, a pedal rudiment, and stomodaeum.
Pretorsional veliger larva (36-48 hpf) The mantle and mantle cavity form. The larva has a velum, apical organ marked by apical cilia, mouth opening, and pedal rudiment with anlage of operculum.
Post-torsional veliger larva (60 hpf) The mantle lies over the back of the head and the velum gradually splits ventrally, the operculum apears.
Metamorphotic (competence) stage (72 hpf) Eye rudiments and cephalic tentacles begin to form in the prevelar area. The anlage of the radula becomes visible.
Encapsulated juvenile Velum is completely lost; eyes and cerebral tentacles are formed.
Hatchling (96 hpf) The encapsulated juvenile hatches and shell mineralization begins.