Anomalies in Rat, Mouse, and Rabbit Eggs

Abstract

Records were kept of 7284 rat eggs, 1120 mouse eggs, and 221 rabbit eggs. Amongst these were 22 rat eggs, 21 mouse eggs, and 1 rabbit egg that were unusual: "giant" eggs of about twice the normal volume, primary oocytes recovered from the fallopian tubes, probable instances of gynogenesis and parthenogenesis, eggs showing abnormalities of fertilization such as the presence of a single pronucleus or of a male and two female pronuclei, and 2-cell eggs with a binucleate blastomere. These anomalies are discussed and attempts are made to explain their occurrence.