Formation of a Reservoir of Sperm in the Oviduct

A reservoir of sperm in the initial segment of the oviduct has been found in several species of domestic and laboratory mammals. Evidently, the reservoir serves to ensure successful fertilization by providing the appropriate number of sperm in the appropriate physiological state for fertilizing oocytes soon after they enter the oviduct. Recent evidence indicates that sperm are trapped in the reservoir by binding to specific carbohydrate moieties on the surface of the mucosal epithelium of the oviduct. A bovine seminal plasma protein has been identified that associates with sperm and confers on them the capacity to bind to the carbohydrate moiety.     

Polyploidy in the common tree toad Hyla versicolor Le Conte

A karyotype of the first known naturally occurring anuran polyploid in North America is described. Hyla versicolor, the common tree toad, is tetraploid (2n-->4n=48). Individual chromosmes representing, each set of four of the Hyla versicolor karyotype correspond closely with those of the diploid (2n = 24) Hyla andersonii karyotype.