2 7 0
L A U R I S A X E N E T A L .
FIG. 1 2 . (a) Electron micrograph of the periphery of a polarized pretubule ( P T ) .
Some slightly enlarged tubular structures of the endoplasmic reticulum ( T ) and small
L A U R I S A X E N E T A L .
FIG. 1 2 . (a) Electron micrograph of the periphery of a polarized pretubule ( P T ) .
Some slightly enlarged tubular structures of the endoplasmic reticulum ( T ) and small