The eggs of two common cirripedes, Balanus balanoides and B. balanus, have been analysed at different stages of development for their lipid content.

Triglyceride and phospholipid are the main lipid components; small amounts of free fatty acids, lipochromes, sterols, and some very non-polar material (possibly hydrocarbon) are also present.

Lecithin followed by phosphatidyl ethanolamine make up a large proportion of the phospholipid fraction.

The fatty-acid spectrum is similar to that of other marine animals being rich in unsaturated fatty acids of which eicosapentaenoic (20:5) and docosahexaenoic (22:6) predominate.

Triglyceride is lost during development.

Initially some lecithin and phosphatidyl ethanolamine are lost during development, but they accumulate in the late stages.

Cardiolipin shows a marked increase in quantity during the late stages; this is presumably associated with increased cellular differentiation.

There is a tendency for all the components to approach the values for the adult bodies—taken when lipid reserves are minimal—as the embryos develop.