the terms metencephalon and myelencephalon are only meaningful in mammals and birds[Neuroanatomy of the Zebrafish Brain]. In zebrafish, with the exception of the cerebellum, the ventral remainder of the metencephalon can be separated only arbitrarily from the more caudal myelencephalic portion of the medulla oblongata and thus these are not distinguished in ZFA[ZFA].

https://github.com/cmungall

http://upload.wikimedia.org/wikipedia/commons/5/54/EmbryonicBrain.svg

http://purl.obolibrary.org/obo/NCBITaxon_7955

The anterior of two brain vesicles formed by specialization of the rhombencephalon in the developing embryo. It gives rise to cerebellum and pons. [TFD][VHOG], Anterior part of the hindbrain ventral to the cerebellum[BIRNLEX:965].

epencephalon

uberon

The early development of most vertebrate brains is similar (...). The zebrafish neural tube follows the same basic differentiation pattern as the mammalian neural tube (reference 1); The brain develops from three embryonic enlargements of the neural tube, which later differentiate into five regions. A forebrain differentiates into telencephalon and diencephalon. The midbrain, or mesencephalon, remains undivided. The hindbrain divides into the metencephalon and myelencephalon. Cavities within the brain enlarge to form a series of interconnected ventricles (reference 2).[well established][VHOG]

UBERON:0001895

• pons
• cerebellum

• future metencephalon

• white matter of metencephalon
• pons
• cerebellum
• trigeminal nerve root
• facial nerve root