STAGE 29/30. Age 1 d., 11 h.; length 4.0-4.5 mm.

Ext.Crit.: Gray eye cup showing through for the first time. * Fin transparent up to the base over its whole length*. Tail bud distinct.

Int. Crit.: Chiasmatic ridge rostrally separated from lamina terminalis by shallow groove. * Nerve fibres extending over 50-60% of length of spinal cord*. *Eye vesicle invaginated, but central portion still convex*.

*Head somites II and II much reduced; 24-25 somites segregated, segregation reaching tail*. Endocardial heart alange a short tube, closed at both ends; pericardial cavity surrounding endocardial anlage on lateral and ventral sides*. Minor lumen indicated in collecting tube of promephros anlage, and first appearance of glomus.

Floor of Pharyngeal cavity somewhat rasied in front of liver diverticulum.