Calogero J A
J Neurosurg. 1977 Oct;47(4):605-8. doi: 10.3171/jns.1977.47.4.0605.
A male infant had spells of tachypnea leading to apnea. He had vermian agenesis and and unsegmented midbrain tectum. This identifies the time of teratogenesis at about embryonic stage XVII to XVII (40 days gestation).