On the Chromosome Morphology ofHumbertiella Indica Saussure

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Abstract
A detailed chromosome morphology and meiosis in Humbertieua indica Saassure have been presented in this paper. The diploid number of chromosomes in this species is 31 in the male, with an XO system of sex determining mechanism. The second division metaphase shows two types of plates-one with 16 and the other with 15 chromosomes. The mitotic chromosomes have been classified into eight types. The X chromosome is the longest in the complement and has a secondary constriction very near the primary one. The remaining chromosomes are all metacentric ones with the primary constriction either median or sub-median in position. Three pairs of chromosomes are provided with secondary constriction. The X chromosome is negetively heteropycnotic in the earlier spermatogonial complements and is never peripheral in position. It is reductional in the first division and equational in the second. The meiosis is normal except for the fact that the X chromosome is expelled out from the spindle into the cytoplasm at prometaphase of the first division but again enters the nucleus at a very late anaphase I stage. The bivalents are of non-chiasmate type.