Fig. 2

Cirrate egg capsules and embryos described and pictured by the late Dr. Sigurd von Boletzky. a Specimen A: longitudinally opened egg capsule with chorion, large external yolk sac, and embryo (dotted outline). b Specimen B: intact egg capsule (left) and extracted chorion (right) with large external yolk sac and embryo (dotted outline). c Specimen B: extracted embryo detached from external yolk sac, ventral view. d Specimen C: intact egg capsule with irregular structuring (left) and longitudinally opened egg capsule exposing chorion, large external yolk sac, and embryo (right). e Specimen D: intact egg capsule with longitudinal striations. f Specimen E: longitudinally opened egg capsule with chorion, large external yolk sac, and embryo. g Specimen F: intact egg capsule with longitudinal striations (left) and longitudinally opened egg capsule with chorion, small external yolk sac, and embryo—note the conspicuous gap between chorion and egg capsule (right). h Specimen F: extracted embryo detached from external yolk sac, dorsal (left) and ventral view (right). a–h Modified after Boletzky (1982). ar = arm, bh = branchial heart, ch = chorion, ec = egg capsule, em = embryo, es = external yolk sac, ey = eye, fc = fin cartilage, fi = fin, fo = funnel organ, fu = funnel, gi = gill, gm = gelatinous matter, in = intestine, is = internal yolk sac, ma = mantle, su = sucker. Scale bars = 1 mm