Simple adenomata were observed in a woodchuck (_Arctomys monax_). This diagnosis is made with the appreciation that nodular regeneration of the liver after damage and in cirrhosis sometimes suggests tumor, but with adenomata an increase of supporting framework may occur. The liver of this animal presented numerous .3 to 10. cm. irregularly spherical, encapsulated, firm or slightly resilient, brown masses which under the microscope consisted of large pale vacuolated cells in columns or strands not connected with bile ducts. The last feature speaks in favor of the diagnosis of adenoma. The damage to the organ was probably considerable and the portal circulation must have been impeded since passive congestion and ascites were present. Enteritis and nephritis seemed the causes of death. Adenomata or fibroadenomata of bile duct origin were seen in four animals, a Red Fox (_Canis vulpes pennsylvanicus_), a Gray Fox (_Canis cinereo argenteus_), a Jaguar (_Felis onca_) and a Common Deer (_Mazama virginiana_). The first two present similar pictures, pinpoint to 8. mm., gray, well outlined areas some of which are clearly cystic, others opaque and more solid. In the first fox a larger mass was found near the hilum. Careful study and consultation has failed to discover parasites in these cases, although their presence was strongly suspected, so that we were forced to conclude, in view of the rather typical microscopic picture, that they are adenomata of bile duct origin. Their scattered distribution, but with a tendency to be more numerous beneath the capsule, corresponds with a human case just brought to my notice. The mass in the liver of the deer was single and resembled an infarct, with cysts exposed by cross section. This tumor was found on the diaphragmatic surface of the right lobe. Tumors of an atypical, therefore malignant, epithelial variety were found four times, in an Alpaca (_Lama pacos_) and three parrakeets; these birds are very prone to have all kinds of tumors. The records of the first animal could not be as satisfactory as might be desired because of an advanced state of decomposition but there was a carcinoma- like growth of the gall-bladder area and a large hard alveolated tumor occupying one-half of the liver. The colon had been involved by the former, with perforation. Two of the parrakeets showed a simple carcinoma with well developed fibrous tissue bands running in all directions through the large mass. The whole growth was comparable to the usual picture of these massive tumors when they are primary in the liver. All these three cancers seem to take their origin in the liver cells but the third had such an interesting involvement of the connective tissue that its minute anatomy will be given; it was denominated adenocarcinoma sarcomatodes.