degradative changes in the nuoleolar RNA, setting in before its
dissolution. The agreement between cytoplasmio and nuoleolar RNA
in early stages contrasts drastioally with the variable RNA of
the nucleoplasm, which shows little resemblance to that of the
other two components. If ribosomal RNA is not turning over in
the growing oooyte a contribution of nucleolar RNA of a ohanged
composition in the later stages may be expeoted to influenoe
the oytoplasmio RNA only moderately, being diluted by preexisting
RKA, A slight increase of the oytoplasmio guanine/
uraoil quotient is nevertheless found with age, whether this is
due to the nuoleolar change or has othsr causes.
SUKURY: The base oomposition of nucleolar RKA from young and
large (near maturity) starfish oooytes differs, the latter RNA
having a higher guanine/uraoil ratio. Only in young oooytes
has the nuoleolar RNA the same oomposition as oytoplasnio RKA,
whioh ohanges only slightly during development. Nuoleoplasmio
RNA shows no resemblance to the other two kinds of RNA.
The work was supported by the Swedish Canoer Sooiety. I am
indebted to Dr. B. Swedmark and the Kristineberg Zoologioal
Station at Fiskebflokskil, Sweden, for supplying animals. Excellent
teohnioal assistanoe was given by Mrs. 1, Sktild-