In probably all members of the genus Crocodilus at least is found, on the thick swelling on the right and on the left side of the neck and trunk, a small, flat pit which has the appearance of the opening of an integumental gland. The pits are present also in the scales of the throat, under the side of the neck, sides of the body, lateral and ventral surfaces of the anterior half of the tail, and the legs. They are near the hinder border of the scales. Only occasionally are two pits found in one scale. These pits are found in the gavials but are absent in some, probably all, alligators. A small knob projects from the center of some of the pits. These pits are not openings of glands but have about the same structure as the pits seen in the head. The integumental bones in the Crocodilia originate in the connective tissue of the cutis. Investigations in young animals show that these bones usually take their origin in the under and middle layers of the cutis and generally work towards the periphery. B. THE ENDOSKELETON _I. The Vertebral Column._ [Illustration: FIG. 16.--Skeleton of Crocodile. _D_, dorsal region; _L_, lumbar region; _Sa_, sacral region; _Ri_, ribs; _Sc_, scapula; _H_, humerus: _R_, radius; _U_, ulna; _Sta_, sternum abdominale: _Fe_, femur; _T_, tibia; _J_, ischium; _C_, caudal vertebræ. (From Claus & Sedgwick.)] The vertebral column consists of about sixty-five vertebræ, which may be separated into the usual regions; there are nine cervical, ten dorsal, five lumbar, two sacral, and about thirty-nine caudal. It is likely that the number of caudals may be subject to frequent variation; one complete skeleton had sixty-five vertebræ in all, another had sixty-eight. A complete skeleton of the crocodile (species not known) had sixty vertebræ. A thirteen-foot skeleton at Western Reserve University had only sixty-one vertebræ, but some of the caudals were evidently missing. Two skeletons of _C. porosus_ in the museum at Singapore had sixty and sixty-three vertebræ respectively. A skeleton of _Tomistoma schlegeli_ in the same museum had sixty vertebræ. _The Cervical Vertebræ._ Since all of the cervical vertebræ bear ribs, we shall assume the distinction between them and the dorsal vertebræ to be that the ribs of the latter meet the sternum, while those of the former do not reach to the sternum. Assuming this distinction, there are, as was said above, nine cervical vertebræ. [Illustration: FIG. 17. FIRST FOUR CERVICAL VERTEBRÆ OF A CROCODILE (_C. vulgaris_). (From Reynolds, partly after Von Zittel.) 1. pro-atlas. 2. lateral portion of atlas. 3. odontoid process. 4. ventral portion of atlas. 5. neural spine of axis. 6. postzygapophysis of fourth vertebra. 7. tubercular portion of fourth cervical rib. 8. first cervical rib. 9. second cervical rib. 10. convex posterior surface of centrum of fourth vertebra.]