NUMBER AND BEHAVIOR OF THE CHROMOSOMES IN CAVIA COBAYA 1 (THE COMMON GUINEA PIG). MARY T. HARMAN AND FRANK P. ROOT. KANSAS STATE AGRICULTURAL COLLEGE. 2 INTRODUCTION MATERIAL AND METHODS. ... -4 DESCRIPTION OF MATERIAL 1. Spermatogonial divisions 75 2. The growth period 3. Spermatocyte divisions 7 6 DISCUSSION SUMMARY -p LITERATURE CITED 7O , DESCRIPTION OF PLATES 82 INTRODUCTION. Since the guinea pig has been used extensively in genetic experiments and since investigation has revealed in many in-stances a close correlation between the genetic behavior and the number and behavior of the chromosomes of many organisms, the number and behavior of the chromosomes of the guinea pig is of interest alike to the cytologist and the geneticist. According to Harvey (1920) there is a wide difference of opinion concerning the number of chromosomes observed in Cavia. Von Bardeleben (1892) reports sixteen spermatogonial chromo-somes and eight chromosomes in the spermatids. Flemming (1898) says that there are probably twenty-four somatic chromo-somes. Moore and Walker (1906) give the number as thirty-two in the spermatogonial cells and sixteen in the primary and secondary spermatocyte cells. Stevens (1911) says that there are about fifty-six spermatogonial chromosomes and tweni\ eight chromosomes in both the primary and secondary spermatu-1 Dr. H. L. Ibsen furnished the guinea pigs for this study. P. VV. Gregory assisted in the fixation and dehydration. The drawings were made by I Prince. 2 Contribution from the Zoological Laboratory, Kansas State Agricuhma! College No. 851. 73
BioStor
