All are true about Somites except:-

The post otic pa of paraxial mesoderm form bilateral solid cord of cells extending along the side of notochord beneath the neural tube. It undergoes segmentation to form series of paired somites. The somites are differentiated into ventro medial (sclerotome)and dorso lateral pa (dermomyotome) The somites appear between 20-30 days of development and by the end of first month, 44 pairs of somites are laid down. Thus, the 4th week of development is known as somite period. Out of 44 pairs of post otic somites: 4 are occipital, 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 8-12 coccygeal.