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In sagital view the pronephric nephron primordium appears as a disk shaped group of cells with no morphologically distinct tubules or glomeruli (TOP).The anterior tips of the pronephric ducts lie directly adjacent to the lateral edges of the nephron primordia.

Sagital sections at 32-33 hpf reveal the first signs of pronephric nephron morphogenesis. The primordium at this stage appears to be partitioned into lateral and medial domains in the regions of the future tubules and glomeruli respectively.

The morphological distinction between tubule and glomerulus is also apparent in sagital section where paired oval masses of presumptive glomerular cells are observed at the midline and pronephric tubules are seen emanating from the lateral aspect of the forming glomerulus (BOTTOM).