Abstract
The chromosomes of the following three species of hydra were investigated: Hydra vulgaris attenuata. Pall., Hydra circumcincta P. Sch. and Pelmatohydra oligactis (Pall.)
The number of chromosomes in Hydra vulgaris attenuata was found to be 32 in diploid and 16 in haploid. The chromosomes show no sexual difference, so far as the morphological feature is concerned. Hydra circumcincta shows 30 chromosomes in diploid and 15 in haploid. The diploid number in Pelmatodydra oligactis was given as 30.
The chromosomes were morphologically analized for every species and karyological comparison was made among them.
