Univ. California Publ. Geol. Sci. 36(1): 1-146. Tabs. 19 figs. 14 pls. July 24, 1959.

–An important survey and partial revision of the two orders, emphasizing the North American fossil record. Reviews the phylogeny of the Trichechidae (3-5); proposes a new suprageneric classification of sirs., introducing the new subfamily names Prorastominae (5), Protosireninae (6), and Halianassinae (8). Describes Caribosiren turneri, n.gen.n.sp. (Middle Olig., Puerto Rico; 8-21), and Halianassa vanderhoofi, n.sp. (Late Mioc., California; 23-44). Describes partial skulls and other material of Halianassa sp. indet. (Mioc., Baja California; 44-49; later made the type of Dusisiren reinharti Domning, 1978) and Eotheroides sp. indet. (Late Eoc., Egypt; 53-56). Discusses the morphology and evolution of the lacrimal, mesethmoid, nasal, and frontal bones in sirs. (57-62), and reviews other fossil sirs. in passing. Reviews the synonymy and morphology of Desmostylus (64-89); describes Vanderhoofius coalingensis, n.gen.n.sp. (Mioc., California; 90-93), Paleoparadoxidae [sic], n.fam., Paleoparadoxia, n.gen., and P. tabatai, n.comb. (Mioc., Japan & California; 94-100). Discusses the habits, phylogeny, and classification of the Desmostylia (101-109), concluding that the Sirenia, Desmostylia, and Proboscidea form a monophyletic group within the Paenungulata.