STAGE 32 Age 1 d., 16 h. length 4.5-5.1 mm.

Ext. Crit.: Eye cup horse-shoe-shaped standing out distinctly. *Length of tailbud about 1 ½ x its breadth.*

Int. Crit. Hypophyseal cell strand detached from ectoderm; roof of Ivth ventricle very thin. *first nerve fibres passing from nasal placode to brain; distinct toor of n. glossopharyngeus*. Layer of nerve fibres along spinal cord terminating at level of cloaca." Cavity of primary optic vesicle disappeared except for region near optic stalk; margins of optic cup, forming chroid fissure, touching each other*; first pigment in outer layer of optic cup.

*First apperance of anlage of ductus endolymphaticus*.

*About 26 post-otic somites formed*. Chordal epithelium and elastica externa formed at base of tail. Posterior end of endocardial tube broadened as anlage of sinus venous; short medial postcardinal persent. *2^nd nephrostome funnel completed *; small lumen in anterior portion of Wolffian duct; rectal diverticula indicated.

*First contact of ectoderm and entoderm in 4^th visceral pouch (formation of 2^nd brachial arch); 5^th visceral pouch indicated; paired lung anlage clearly visible*.