STAGE 59 Age +/- 45 d.

Ext. Crit.: Tentacles beginning to shrivel up. *Stretched forelimb reaching down to base of hindlimb*. Guanophores appearing near base of forelimb (adult skin area); anterior border of adult skin area on abdomen not yet sharp; appearance of irregular dark spots on back.

Int. Crit.: Areas of metamorphosing skin well circumscribed, that of trunk extending partly over telencephalon; lymph sacs beginning to develop underneath metamorphosing skin areas; first symptoms of degeneration in larval skin between trunk and hindlimb areas of metamorphosing skin. *Cross section area of largest lumbar motor column nuclei of spinal chord 5 x, of brachial motor column nuclei up to 4 x that of average non-motor nuclei*.

*Appearance of operculum fen. ovalis and pars interna plectri as mesenchymatous condensations*. *Intercellular melanin deposits underneath epidermis, around blood vessels and between muscle fibers of tail*. *Paired anlage of sternum blastematous*. Ilia connected to last vertebra by connective tissue. New generation of mesonephric tubules formed in reorganization process. *First meiotic division in testis*.

*Second row of tooth germs formed*; epithelial bodies detached from visceral pouches. *Histolysis in non-pyloric part of stomach, and pancreas*.