_Dorsals._--A few of the anterior dorsals have strong hypapophyses. The centra of all are long and stout. The neural canal is smaller than in the cervical region; it has strong neurapophyses, which develop long and depressed diapophyses. The neural spines are low and broad. The zygapophyses are developed on the laminæ, and do not project upwards as in the cervical region. The _lumbars_ are much like the dorsals, except that they are longer, and have very large and depressed diapophyses, which project somewhat upwards. _Measurements._ M. Length of centrum of a posterior cervical ·049 Height of neural canal ·015 Fore-and-aft diameter of neural spine ·023 Length of diapophysis ·023 _Dorsal._ M. Length of centrum ·0555 Length of hypapophysis ·018 Fore-and-aft diameter of neural spine ·030 _Lumbar._ M. Length of centrum ·057 Fore-and-aft diameter of neural spine ·0285 Diameter of diapophysis ·029 The dermal scutes are long ellipses, deeply pitted on one side, but without a trace of a keel. Their edges show no signs of sutural union. The bones described indicate a reptile about fifteen feet long. They were found near Smith's Fork, Wyoming. Crocodilus parvus, _sp. nov._ A small reptile represented by sixteen vertebræ and a portion of the pelvis. The _cervicals_ have short centra, with very deep articular cups and hemispherical heads: the latter have a prominent rim around the base. The hypapophyses are short, stout, and very nearly vertical in direction; the sides of the centra are channelled by a deep vertebraterial canal; the parapophyses are developed very low down, and are very prominent. The diapophyses are developed partly from the centra and partly from the neurapophyses; they are stout and very short. The facets for the ribs are developed in the usual place. The neural arch is rather high, and forms a small, narrow canal; the proportions of the neurapophyses and neural spines are about as in _Alligator mississippiensis_, but the zygapophyses are not so prominent. The _dorsals_ show a considerable increase in size over the cervicals; the centra become elongate, and the articular cups shallower and transversely oval. Several of the anterior vertebræ retain large hypapophyses. In the dorsal region the diapophyses are developed from the neurapophyses alone, and at a considerable height above the neuro-central suture; they are long and depressed. The zygapophyses and neural spines present no peculiarities of structure.