Part I.—Crania of Tyranosaurus and Allosaurus. By Henry Fairfield Osborn, pp. 1-30, pll. i-iv and text figures 1-27. 1912.

Part II.—Integument of the Iguanodont Dinosaur Trachodon. By Henry Fairfield Osborn. Pp. 31-54, pll. v-x, and text figures 1-13. 1912. Parts I and II are issued under one cover. Price, $2.00.

Part III.—Craniometry of the EquidÆ. By Henry Fairfield Osborn. Pp. 55-100, text figures 1-17. 1912. Price, 75 cents.

Part IV.—Orthogenetic and Other Variations in Muskoxen, with a Systematic Review of the Muskox Group, Recent and Extinct. By J. A. Allen. Pp. 103-226, pll. xi-xviii, text figures 1-45, 1913. Price $2.50.

Part V.—The California Gray Whale (Rhachianectes glaucus Cope). By Roy C. Andrews. Pp. 229-287, pll. xix-xxvii, text figures 1-22. 1914. Price, $2.00.