STAGE 62 Age +/- 49 d.

Ext. Crit.: *Head still somewhat broader than cranial part of trunk*. Tentacles short, straight. *N. Olfactorius shorter than diameter of bulbus olfactorius*. Corner of mouth still infront of eye. Thymus gland somewhat protruding. * 3^rd arterial arch ("larval aorta") seen at distance of its own diameter in front of adult skin area of forelimb*. *Opening of operculum reduced to curved slit*. *Forelimb at level of middle of heart*. Anterior border of adult skin area on abdomen entirely sharp, mostily nicked medially. Ventral fin disappeared from abdomen.

Int. Crit.: Areas of larval skin on head beginning to shrivel. *Tiny "Stirnorgan" situated in front of rostral end of brain cavity*. Tear furrow leading from opening of naso-lachrymal duct to eye. *Lower eyelid forming*. Dorsal outlets of for. prooticum confluent; *proc. muscularis palatoquadrati and cartilago tentaculi disappeared; angle between palatoquadratum and anterior floor of cranium 65°; appearance of squamosum and fusion of inner and outer lobes of goniale*. Appearance of m. petrohyoideus. Intervertebral cartilage calcifying in pre-urostyle region; *cartilaginous connection of 3^rd pair of ribs with vertebral column*. Pars lateralis of m. ileolumbalis and m. coccygeo-sacralis formed. *Signs of atrophy in notochord over entire length of tail; degenerative hypertrophy of mesenchymatous perichordal tube and vertebral arches of tail*. Medial ends of cartilaginous sternal anlagen forming sternal pouches. *Appearance of arteria cutanea magna*; disappearance of arteries of filter apparatus. *Appearance of musculo-thyroid veins; complete disappearance of lateral veins*; disappearance of pronephric sinuses and paired portions of medial postcardinal veins; disappearance of pharyngeal vein. Of 2^nd and 3^rd nephron of pronephros only nephrostomes remaining; * 2^nd nephrostome fused with ostium tubae; portion of Wolffian duct between pro- and mesonephros disappeared*.

*Middle ear situated below caudal margin of eye*. *Number of intestinal revolutions reduced to about 2 in outer and 2 in inner spiral; epitheium of oesophagus, non-pyloric part of stomach, duodenum and ileum reconstituted to more or less continuous layer*, that of non-pyloric part of stomach already differentiating.