Although the specimen is so young, the anterior foramen of the atlas is, nevertheless, inclosed by bone, and though the line of separation between the atlas and axis is visible on the sides, the fourth cervical is anchylosed to the third at the top of the centrum. Although the neural spines, metapophyses, and transverse processes of the thoracics are much shorter than those of the young _semijunctus_, the epiphyses are as large or even larger than in that specimen. The neural arches are also noticeably thicker than in _semijunctus_, and the centra are rounded inferiorly rather than carinated. The neural spines are much more nearly erect than in the adult Barnegat and Newport skeletons, but, as mentioned on page 41, this is probably a character of immaturity, and is shared by _semijunctus_. The differences as regards the form of the centra and neural arches die away among the lumbars, and these vertebræ and the caudals are, with a due allowance for greater immaturity, very similar to those of _semijunctus_. The seventh thoracic is like the sixth in form, and is without a transverse process. It thus resembles the same vertebra in _semijunctus_. The eighth, however, has an ill-defined facet on the side of the metapophysis and a second facet a little above the upper border of the centrum. The eighth pair of ribs has only a single terminal articular facet. The ninth thoracic has a short, thick transverse process, about in line with the upper surface of the centrum. The transverse process of the seventh caudal is perforated on the right side by a foramen. The transverse processes are last traceable on the ninth caudal, the neural spines on the tenth caudal, and the neural arch on the eleventh caudal. Eight chevron bones are preserved, but probably two more were present originally. Ten pairs of ribs are present. The first is much broader in the proximal half than in the distal half, but the distal end is slightly expanded. The first seven pairs possess both head and tubercle, but the eighth, ninth, and tenth have only a single terminal articular facet. The sternum, which consists of five segments, is similar in form to that of _semijunctus_. The two sides of each segment are united. The posterior emargination of the third segment, and those of both ends of the fourth and fifth segments are small. The scapula and humerus are like those of _semijunctus_ in form. The remaining parts of both pectoral limbs are lacking. Without more material, and especially some skeletons of adults, it is difficult to decide what importance should be assigned to the differences observable in the cervical and thoracic vertebræ of this young Bering Island specimen. The measurements of the skeleton are included in the table on pages 47 and 48. EXTERNAL CHARACTERS.