The vaginal smear, mating, egg transport and preimplantation development in a wild guinea-pig, the cuis (Galea musteloides).

Observations were made on vaginal smear pattern, mating, rate of egg transport and preimplantation development in cuis. In 39 of 45 females (87%) vaginal opening occurred within 2 days of pairing, and in 44 (98%) within 5 days; 36 of the 44 females (82%) mated. By the morning of Day 2, eggs were no longer recovered from the ampulla, having all passed into the isthmus, where they remained till Day 4, p.m. Uterine entry was complete by Day 5, a.m. Uterine blastocysts were no longer recoverable on the morning of Day 6. There was no evidence of blastocyst expansion or zona shedding before implantation.