After nuclear maturation the eggs of Psammechinus (Ps.) miliaris are still ‘underripe’ with respect to their cytoplasm. This phenomenon is particularly conspicuous in Ps. miliaris from the Swedish west coast (see, for a summary, Runnström, 1949). In the small individuals of Ps. miliaris dredged from a depth of 30–40 metres this state of underripeness may last for months, so that full cytoplasmic maturity may be reached only in the latter half of August (Lindahl & Runnström, 1929). The littoral form of Ps. miliaris, on the other hand, has already attained cytoplasmic maturity in the latter half of June. Temperature conditions evidently play a decisive role in the phenomenon.

Copyright © 1953 by Company of Biologists
1953
You do not currently have access to this content.