On The Affinities of Leptarctus primus of Leidy American Museum of Natural History, Vol. VI, Article VIII, pp. 229-331.

"On The Affinities of Leptarctus primus of Leidy" by Jacob Lawson Wortman is a scientific article from the late 1800s that examines the physical characteristics of an extinct animal called Leptarctus primus. The study looks closely at the fossil to figure out where it fits within the raccoon family and how it might be related to other similar creatures. Wortman keenly observes and documents how the animal's dental and skeletal structure, particularly its strong canine teeth and unusual premolars, provides significant clues about its place on the family tree, pointing toward it being a link between common raccoons and a peculiar relative. The research contributes to a deeper understanding of the history of the raccoon family and the diversity of species that have existed highlighting key evolutionary changes over time.