REPRODUCTIVE CYCLES AND SUPERFETATION IN PŒCILIÏD FISHES

A graphic summary of the relations of growing ovocytes, mature ova, the fertilization process, the broods of embryos retained in the ovary and the time of birth is offered in Table IV. Each group represents the situation within a single ovary at the height of the reproductive season and at the moment in which a brood is born. The term brood is used to indicate a group of growing and differentiating ovocytes of approximately equal development up to the time of fertilization and also the embryos produced by the fertilization of these ova up to the time for birth. No quantitative relations are implied concerning comparative size of ovocytes or embryos in different species nor of comparative lengths of time that embryos are retained in the ovary.A study of Table IV leaves one with the impression that the extreme type of superfetation in Heterandria formosa might have arisen from the simpler type as illustrated in Pœcilistes pleurospilus. The argument also appears to be defensible that the simpler type of supe...