Somite formation in cultured embryos of the snapping turtle. Chelydra serpentina.

A simple, reliable method for the in vitro cultivation of snapping turtle embryos was demonstrated. This technique was used to study somite formation in explants containing segmental plates. Segmental plates formed a full complement of somites whether the neural tube or the neural tube and notochord was present. Explanted snapping turtle segmental plates formed an average of 6.6 +/- 1.2 somites. Removal of the node region or tail bud from cultured intact embryos led to a cessation of somite formation after an additional 6.1 +/- 1.8 somites had formed. These results indicate the number of somites the snapping turtle segmental plate will form. Also, the number of somites formed by explanted segmental plates showed only slight variation over a wide range of segmental plate lengths. It was concluded that while snapping turtle segmental plates formed significantly fewer somites than chicken or Japanese quail segmental plates, they were similar to the avian explants in their ability to form a consistent number of somites regardless of the length of the segmental plate.