Cittarium pica. Embryonic development in the first 97 days post-fertilization: (A) recently spawned oocyte with dissolved germinal vesicle and a jelly layer (jl). (B, C) Expulsion of polar bodies (pb). (D, E) First and second cleavages result in macromers (A, B, C and D) and micromers (a, b, c and d). (F, G) Third and fourth cleavages. (H) Morula. (I) Blastula. (J) Gastrula with cilia (cl) and stomodeum (st). (K) Intra-capsular trochophore larvae with prototroch (pr). (L) Hatched trocophore with protoconch (pc). (M) Pre-torsional veliger with ciliated velum (v) and retractor muscle (rm). (N–S) Post-torsional veliger with foot mass (fm), integumental attachment (ia), operculum (op), cephalic tentacle (ct) and propodium (p), eye spot (es), cl in p and in mantle cavity (m), epipodial tentacles (et), apophysis (ap) on the p, otolith (ot) and snout protrusion (s). (T, U) Formation of two, three and four tubules (tb) in the ct. (V) Crawling veliger with foot (f). Bar size = 80 μm.