Ratio of wet weights are averaged over all litters or uteri at each age.
On day 59, the development of branched uteri containing many fertile immature eggs in a worm was observed and by day 75, three worms showed similar stages of development.
The ovaries, which are blind-ended and strongly coiled, are located near the posterior end of the adult worm and lead into the oviducts which widen abruptly into the uteri.
Thereafter, the paired uteri gradually broaden and run almost parallel occupying the greater part of the length of the worm to the anterior region where they gradually narrow.
Uteri of female worms contain eggs, developing larvae as well as microfilariae varying in number between 180,000 and 220,000.
All recipients were laparotomised 9-20 days after transfer to examine the number of swellings in the uteri (implantation sites).
For experiment 2 (see below), primary cell cultures of rabbit fetal fibroblasts were derived from 12-day-old fetuses removed from rabbit uteri by caesarean section.
The worm uteri were distended with eggs, and uterine egg counts of 10 worms showed a mean of 243 ^ 6 eggs/worm.
