Note 3 — Chapter VI · The Species Question
Reading edition
That is, resemblances in nuclear division stages are not correlated with corresponding degrees of resemblance in somatic characters. It is not generally held that the shape or size or number of chromosomes is correlated with any external characters. It is the presence of hypothetical factors or genes which are held to be correlated with somatic characters and their number or arrangement in a chromosome is not in any way related to their character.