180 [October, This bird I procured during the summer, but it is found on the fresh water courses and marshy lakes of California throughout the year. The nest, com-posed of a few loose straws 01 rushes, is placed on the ground, near the edge of the marsh, and contains four eggs of a dirty white color. Description of four new species of Kivostemum. By John Le Conte. The genus Kinosternum, as defined by the latest writers on Herpetology, is described as follows : Head subquadrangular, pyramidal ; cranium with only one rhomboidal plate; jaws a little hooked, papillae under the chin. Sternum oval, moveable, both anteriorly and posteriorly on a fixed piece, furnished with eleven plates, wings short, narrow, subhorizontal, the axillary plate very large, the in-guiual still larger. Vertebral scuta slightly imbricate. Tail long, in the males unguiculate. A comparison is made of this genus with Staurotypus, to which it in reality has some affinity, but not so much as M. Dumeril supposes. It, indeed, does not fall into the same group when the Testudinata are properly arranged, but the Staurotypus, as will be shewn hereafter, is extremely different and has a mani-fest relation with the Emysaurtts. M. Dumeril slates that the elastic ligaments which retain the two moveable portions to the fixed intermediate part 'of the sternum, are situated, one under the suture of the pectoral and abdominal scuta, and the other under these la,st and the pectorals. Now it must be observed that the moveable portions of the sternum are not in every species joined by a liga-ment to the middle or abdominal piece; in many it is only the anterior one which is, and which of course turns as upon a hinge ; the posterior portion is joined by a suture, which is only moveable in the same degree as any other portion of the bony frame of other animals which is articulated in a similar manner, its movea-bility depending in a great degree on the length of the teeth of the joining surface, in others the anterior portion is joined partly by ligament and partly by suture, the posterior one by suture only, and therefore not so moveable as in other in-stances. In young subjects this capacity for motion in the so-called valves of the sternum is more apparent, but as they advance in age it gradually diminishes, until in some the three pieces become, as it were, soldered together. In those species where there are really two valves with ligamentous junctions, the box of the shell can be entirely closed, and this connects them in some degree with Cistudo, but this has the sternum joined to the shell by a membrane, whereas in Kinosternum the same thing is effected by bony commissures from prolonga-tions of the abdominal portion. The peculiarities of the sternum will allow the species of this genus to be ar-ranged in three groups. 1st. Those in which it is truly bivalved, and closing entirely the aperture of the cell. 2d. Those in which although the sternum is wide, it by no means closes up the carapace, and is only furnished with an an-terior valve joined to the abdominal portion, partly by ligament and partly by suture, yet fully moveable as if the ligament was extended along the whole of the hinder margin, the posterior valve united by a suture which admits of more or less motion. 3d. The sternum with two joints, both of them completely sutural. In these the different parts are frequently as immoveable as in an Emys. The following description of the genus Kinosternum is offered w r ith the hope that it contains all the distinguishing characteristics possessed by the animals, and that it will be sufficient to separate them from all others of the Testudinata. Kinosternum. Chin with from two to six papillae or warts. Vertebral scuta more or less imbricate ; marginals twenty-three, sternal eleven in number. Sternum composed of three separate pieces, of which the abdominal or interme-diate one is immoveable, the anterior one turning on a partially or entirely liga-mentous hinge, and the posterior articulated to the same piece either by a liga-ment or by a suture, and consequently either freely and entirely moveable, or only more or less imperfectly so. The wings which connect the sternum to the
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