Chromosomic studies in Pheretima californica Kinberg (Meg ascolecidae, Oligochaeta)

Abstract

The authors studied the morphology and the number of chromosomes of Pheretima californica Kinb. by crushing and cutting of seminal vesicles, testis, ovaries, somatic tissue, etc. In the case of the crushing method they used acetic Hematoxylin according to Sáez and Feulgen's nuclear reaction, but in the case of the cutting method only Feulgen's nuclear reaction was employed. Sometimes they used the contrast of Hematoxylin on Feulgen's staining, while in other opportunities they used a water saturated solution of "fast green" to contrast the Feulgen.
They prepared the idiogram of mitotic chromosomes in spermatogonies in different stages of division, counting and studying the chromosomes in the antepenultimate and penultimate spermatogonial mitosis, determining 2n = 30 chromosomes.