External: Invagination of the lens disc but with an open lens pit; a well-defined endolymphatic appendage; elongated and tapering upper limb buds.
Internal: The ventral pancreas (if not detectable earlier) is distinguishable at stages 14 and 15; right and left lung sacs grow dorsad; the ureteric bud acquires a metanephrogenic cap; future cerebral hemispheres and cerebellar plates begin to be visible.
Developmental Stages in Human Embryos by Ronan O'Rahilly and Fabiola Müller.
Published by Carnegie Institution of Washington, Publication 637. 1987.
Stage 14 (PDF 1 MB)
QUESTION: What structure becomes well defined in the ear vesicle?