Crocodilus humilis, Leidy, 1860

Lambe L. M., 1902, New genera and species from the Belly River Series (mid-Cretaceous), Geological Survey of Canada Contributions to Canadian Palaeontology 3, pp. 25-81 : 47

Crocodilus humilis , Leidy.

Crocodilus humilis , Leidy. 1860. Trans. Amer. Philos. Soc. Extinct Vertebrata from the Judith river and Great Lignite formations of Nebraska, p. 146, pi. 11, figs. 9-19 .

Teeth of this species are found abundantly iu the rocks of the Belly River series. They are in the form of elongate cones, slightly curved inward, w^ith two angular longitudinal ridges defining the slightly flattened inner side. They are generally quite smooth, but in some specimens, a distinct folding or corrugation of the surface is observed more particularly in the upper half of small and medium sized specimens. Their bases are slightly excavated. The apices generally show signs of wear.

I^umerous examples also occur of the low, rounded germ-teeth, figured by Leidy, that have a silky lustre, caused by the presence of minute, close-set, discontinuous ridges in the enamel, converging toward the apex. They are, however, sometimes elongated so as to be moderately pointed above.

Belly River series, Red Deer river, 189*7, 1898 and 1901.

Teeth of G. humilis had previously been collected, brit not determined, from the isame series of rocks, as follows: Professor John Macoun, Mackay creek, near "Walsh, a station on the line of the Canadian Pacific Railway, east of Irviue, 1880; Dr, Gr. M. Dawson, Belly river, N.W.T. (Nos. 40 and 41), 1881; Mr. T. C. Weston, Ross coulee, near [rvine, 1884, and Irvine coulee, also near Irvine, 1888.

Figures

Fig. 9. Front lobe of the plastron of another specimen from Red Deer river. One- half the natural size

FiG. 10. Baena antiqua; A, part of the carapace; B, lower surface of anterior lobe of plastron; C, upper or inner surface of anterior lobe of plastron. One-haLf the natural size. The sinuous lines indicate the sutures between the bones, the heavy ones the boundaries of the epidermal shields. The letters are as in preceding figures.

FIG. 11. - —A. Right hind limb of Ornithomimus altus; right lateral aspect. B, foot of the same front view. C, distal end of tibia. D, proximal end of inetatarsals. E, distal end of same. F, transverse section of tibia. Figures one-sixth the natural size. Is, ischium F, femur; p, pubis T, tibia F, fibula a, astragalus; as, ascending process of astragalus; c, calcaneum; t, tarsal bone; II-V, digits. The ischium and pubis are indicated in the position, relative to the femur, in which they were found.

FIG. 12.- Stereocephalus tutus. Tooth, from Red Deer river, A, side view B, end view. Twice the natural size. (Provisionally associated with S. lutas.)

FIG. 13. -Stereocephalus tutus. Dermal plate from Red Deer river one - sixth the natural size. A, side view; B, view from above. Provisionally associated with S. tutus.)

FIG. 14.-—Head of Monoclonius dawsoni, from a sketch in the field; uııe-uvelftlı the natural size. p, parietal or, orbit; oc, occipital condyle q, qnadrate m, maxilla (inner side, showing a row of foramina; h, horn core s, squamosal.

FIG. 15. --Posterior crest of Monoclonius dawsoni, viewed from beneath; slightly less than one-eighth natural size. The numbers give the thickness of the bone, in centimetres, at the points indicated. P, parietal S, squaniosal F, fontanelle.

FIG. 16.-—Sacrum provisionally associated with Monoclonius dawsoni, less than one-seventh the natural size 2 superior view.

FIG. 17.-Tlıe same sacrum right lateral aspect; about one-seventli the natural size, a, a, facet for iliiiui d, diapophysis; np. neural platform: ns, neural spine i, intcrspace .

FIG. 18. Monoclonius canadensis part of the skull from the right lateral aspect: one-eighth natural size. fp, postirontal h, horn core o, orbit: sqnztmoszil p, right lateral extension from parietal j, jugal l, lower jaw.

FIG. 19. -:\ 1Anterior dorsal vertebra of Monoclonius canadensis, one-fourth the natural size. A, front view; B, left side view; a, anterior face of ccntrnm d, (lizpopliysis h, facet for head of rib n, neural canal; s, neural spine t, facet for tubercle of rih z,`prezygapophysis z, post- Zygapophysis