Unlike human blood, the red blood cells in Fish blood and frog blood have a nucleus. The nucleated red blood cells are found in all fish, birds, amphibians and reptiles, whereas mammal red blood cells lack a nucleus.

You'll also notice that frog blood cells are quite a bit larger than human blood cells. Also, frog red blood cells are oval shaped while human red blood cells are round.

These slides were purchased on Ebay and are part of 100 prepared slides " set B"