A 39-year-old man with chronic alcoholism is brought to the hospital after a fall, while intoxicated. He has completely recovered except for a bruise on his shoulder. His only abnormality is low hemoglobin of 9.6 g/dL, the platelets and WBC are normal. Additional tests including ferritin, vitamins B12, and folate are normal. Which of the following findings is most likely to be seen on his peripheral blood film?