Cytochemistry of yolk elements in the Amphioxus egg

Summary The Amphioxus egg develops compound yolk and lipid yolk, besides the cortical vacuoles described previously. The compound yolk elements consisting of carbohydrates, proteins, lipoproteins, and triglycerides originate within the ooplasmic masses that are constituted by the yolk nucleus substance and mitochondria. The lipid yolk elements, which are poorly developed, stain for phospholipids; the exact mode of their formation could not be determined. The behaviour and cytochemistry of organelles (yolk nucleus and mitochondria) have also been described.