Altitude of tail 20 67. Length 6 Ribs. As has already been stated, the cervical ribs were displaced in the present specimen, and measurements of them cannot be given. In a smaller specimen, specifically indistinguishable from the present one, the entire cervical series is preserved with the ribs attached. The first, that articulating with the axis, is very short. The following ones are stouter, but increase only moderately in length, that of the sixth measuring only thirty-five millimeters, while that of the seventh is but a little longer. In the specimen of _C. velox_ described, there is a detached cervical rib sixty-five millimeters in length; it probably belongs with the seventh. The thoracic ribs are simple, somewhat flattened rods, moderately expanded at the proximal end. The greatest convexity is shown about the middle of the series, where the versedsine of the curvature is forty millimeters, the chord being one hundred and sixty. Posteriorly, the short ribs are only gently curved. Lying by the side of the vertebral column, and between the ribs, as they have been pressed down, are a number of flattened, soft, punctulate bones, which are evidently the costal cartilages. Posteriorly four rows of them are seen, lying closely side by side, some of them eight or ten inches in length. The sternum, composed of the same material, has been so crushed and crumpled that its shape cannot be made out. The whole structure here, whether of ribs, cartilages or sternum, reminds one very strongly of such lizards as the Iguana or Monitor. There is no indication, however, in any specimen, of an episternum. MEASUREMENTS OF RIBS. Length, first thoracic rib, (chord) 200 millim. Length, eleventh thoracic rib, (chord) 145 Length, thirteenth dorsal rib 68 Length, eighteenth dorsal rib 64 Length, thirty-fourth dorsal rib 52 The lengths of the different regions, as they lie in their natural relations, are as follows: Skull 0.420 meters. Neck 0.225 Trunk 1.360 Tail 1.460 Total 3.465 11 ft. 7 in. The measurements of an excellent specimen of _C. tortor_ are as follows: Skull 0.630 meters. Neck 0.360 Trunk, (thirty-three vertebrae preserved) 2.370 A very complete specimen of a _Liodon_ in the Museum, in which the _complete_ vertebral column is present, numbering one hundred and seventeen vertebrae, gives the following measurements. The skull is complete, save the most anterior portion. Skull (approximated within narrow limits) 0.700 meters. Neck 0.430 Trunk 1.760 Tail 3.420 Total 6.310 20 ft. 8 in.