Labelled endocasts of the dichobunoid artiodactyls (a,c) D. ilicis (AMNH VP 16141) and (b,d) Homacodon vagans (USNM 482369) in the (a,b) dorsal, (c) ventral and (d) lateral view (scale bar, 5 mm). Abbreviations: bs, brain stem; fp, fissura prima; gr, groove; g3, gyrus 3; llc, lateral lobe of the cerebellum; ls, lateral sulcus; mb, midbrain; ob, olfactory bulb; ot, olfactory tubercle; pa, paraflocculus; pf, paramedian fissure; pi, pituitary; pyl, pyriform lobe; rh, rhinal fissure; sf, sylvian fossa; si, sinus; ssy, suprasylvia; vm, vermis; II–XII refer to cranial nerves. Institutional abbreviation: USNM, National Museum of Natural History, Smithsonian Institution, Washington.