Fig. 1. A in Gastrointestinal helminths of waterfowl (Anatidae: Anatinae) in the Lerma marshes of central Mexico: Some pathological aspects

Fig. 1. A. Intestine of Anas crecca with a transparent nodule of 2 mm in diameter caused by Pseudocorynosoma constrictum penetrating the serosa. B. Proventriculus of Spatula discors with nodules (arrows): some of them whit Tetrameres sp. C. Gizzard of Mareca americana with hemorrhages (arrow) caused by the nematode Amidostomum spp. D. Gizzard of Mareca americana with a nodule of 1.5 × 2 cm in diameter and firm consistency, with the nematode Echinuria uncinata. E. Intestine of Anas crecca showing a nodule in the subserosa, containing the acanthocephalan Filicollis sp. in the intestinal lumen.