Direct (monogenesis) and indirect (metagenesis and metamorphosis) development

Monogenesis is the direct development of an embryo, without metamorphosis, into an organism similar to the parent.  Metagenesis, like the other form of indirect development, metamorphosis, consists of marked changes undergone in a series of successively produced individuals, extending from the one developed from the ovum to the final mature individual.  Unlike metamorphosis, metagenesis involves the production of sexual individuals by non-sexual means, either directly or through intervening sexless generations. 

See Corticospinal tracts (CST), Development, Metamorphosis (or indirect development), Primary motor cortex