Primates are not often affected with degenerative arterial disease, two of the instances observed showing this change confined to the coronary vessels. As might be expected the myocardium in both was affected, and in one animal had a definite concentric hypertrophy. A very interesting case was encountered in a Lion-tailed Macaque (_Macacus silensis_). His heart showed distinct fibrosis of the conducting pathways from auricle to ventricle and of the papillary muscles. No atheroma was present in the aorta, but in the pulmonary distinct sacculations of the Mönckeberg type were found. Mesial degeneration was apparently responsible, but no calcification had occurred. Death was due to acute gastritis. Carnivora present about half the cases seen in mammals and 16 per cent. of the total. Five of the sixteen cases owe their origin to parasitic arteritis and were combined with aneurysms. As will be noted by consultation of the list there is no outstanding accompanying pathology, a fact which makes parasites more important. One case of mesial degeneration, resembling the Mönckeberg type was observed in the thoracic aorta of a bear. Ungulata are generously represented, thirteen cases being recorded distributed rather unevenly between the odd-toed (1 or 8.5 per cent.) and even-toed groups (12 or 2.9 per cent.). The single case in the first group occurred in a Zebra (_Equus burchelli_) wherein was found about the middle of the thoracic aorta a diffuse thickening of media and intima in a circular plaque approximately two centimetres in diameter; it was by no means so well developed as similar lesions in the even-toed ungulates. This recalls the expression of doubt by Zinserling as to the occurrence in the horse of arteriosclerosis similar to that in human beings. The lesions in the Artiodactyla are both in plaques and diffuse, the aorta and its branches sometimes being quite wrinkled but beset with firm elevations with and without calcification. These changes are fairly definite and, although they never attain the development seen in man, resemble the stage of wrinkling and roughness in the preulcerative stage of the human analogue. Two of the cases were associated with dilatations of the mesenteric vessels and with periarteritis, a picture strongly suggesting parasitic infestation; in one case ineffectual search was made, in the other no record is made of the parasites. Renal disease occurred only twice and myocardial damage only once. Chronic pulmonary disease, present thrice, took the form of tuberculosis twice and pleural adhesions with atelectasis once.