GENERAL FEATURES OF THE ELASMOBRANCH EMBRYO AT SUCCESSIVE STAGES, pp. 286-297.
Description of Stages A-Q. Enclosure of yolk by blastoderm. Relation of the anus of Rusconi to the blastopore.
The Works of Francis Maitland Balfour, Volume 1 (of 4) · The Wunder Library — complete classics, free to read, with narration.