Intraendodermal and intramesenteric migration of anuran amphibian germ cells: transmission and scanning electron microscopy.

Primordial germ cells (PGCs) from the dorsal side of midgut endoderm and from within the dorsal mesentery were examined by transmission and scanning electron microscopy. During migration of these cells, lamellipodia and filopodia, develop in a polarized pattern. Large amounts of extracellular material accumulate around the lamellipodia at the leading end of a migrating cell. It is suggested that the polarized pseudopodia function in conjunction with extracellular matrix as the means by which PGCs move en route to gonadal ridges.