The point of chief interest in this relation is the value that can be given to this character. Is it individual, specific or generic? Marsh has called it generic, but we think an examination of the two very complete specimens of _C. tortor_ and _C. velox_ in our Museum will convince any unprejudiced student that he is in error. A comparison of the figures herewith given of the paddles will show their great resemblance, and these two forms of paddles have been figured because the species are the most unlike of any that we know in the genus. As all the small specimens seem to possess this character, and as they cannot be called immature specimens, we believe the character is a specific one. As Marsh says, typically both _Clidastes_ and _Edestosaurus_ have a non-emarginate coracoid, so that neither name could apply to the emarginate form, were it generically distinct. Our Museum also contains both forms of the coracoid pertaining to the genus _Platecarpus_, of which _Holosaurus_ is a synonym. While studying the specimen above described, a striking similarity was observed to several other specimens already determined with confidence as _C. pumilus_ Marsh. A more careful comparison failed to bring out any real differences beyond size, and even this was shown to be very inconstant. The following comparison of the descriptions given by Marsh will be of interest. _C. pumilus._ TEETH. Nearly round at base somewhat curved and with smooth enamel. QUADRATE. The rugose knob near the distal end of the quadrate is similar to that in _C. Wymani_ (just below the posterior superior process is a prominent rugose knob with a deep pit under it), but has no articular pit under it. The hook is comparatively short and has a free compressed extremity. The articular margin is not deflected toward the meatus. CERVICAL VERTEBRAE. Articular face nearly vertical, and having a broad transverse outline with faint superior emargination. The hypapophysis stout and transversely triangular. _C. velox._ Premaxillary and maxillary teeth smooth and subcompressed. The great ala less curved than in _E. dispar_, concave transversely on both surfaces. The alar process has its articular process very narrow in its extension over the great ala. No notch in posterior margin of external angle. On the ridge below the angle and nearly opposite the meatal pit is a strong rugosity which is rudimentary or wanting in _C. dispar_. The posterior margin of the hook is only a narrow tongue projecting towards the meatal pit, instead of a broad articular surface. Articular face transverse.