OCR Text |
Show 1867.] PROF. W. LILLJEBORG ON HALCROSIA AFZELII. 717 Halcrosia frontata. The edges of the jaws are strongly sinuated; and the upper jaw has on each side a deep hollow, to receive the seventh tooth of the lower jaw, which in this instance is the largest, and its two foremost front teeth do not pass through the intermaxillary bone. The teeth are J^j|. The back teeth of the under jaw do not project in between those of the upper jaw, but within them, as in the case of the Alligators. Hind foot of Halcrosia afzelii. Our specimen being imperfect, we have, as regards the feet, the opportunity of examining only one of the hind feet (fig. 2). The web is well developed, but the exterior edge of the foot is not fringed. It has but one row of four somewhat large keeled scales, which do not form any prominent lobe or fringe. The remainder of the outer side of the foot is covered with keeled scales of various sizes. With regard to the plates of the skin, this genus, as is known, is especially distinguished by the peculiar form of the upper plates of the nape. These have also in this species a characteristically broad form, with almost horizontally outstanding keels, and are particularly-large ; but there are but two pairs, and a considerable interval separates the posterior from the anterior dorsal plates ; they have in the middle of their upper surface a shallow longitudinal groove. The cervical plates are six in number, forming a curved transversal row, and are oval and strongly keeled. The dorsal plates form four continuous longitudinal rows, of which the outermost on each side is distinctly, the inmost indistinctly, keeled ; there is, moreover, on each side a couple of imperfect rows, and several scattered plates on the sides of the body. The back and loin have eighteen transversal rows of plates, including the foremost exceedingly small ones. The tail has twelve similar rows between the base and the strongly projecting serrated lobe, or crista. All these plates are as it were sculptured with fine concentric raised lines, as is also the case with the plates of the head and feet. As the end of the tail is missing I am unable to give the number of plates in its crista. The ventral plates are ossified. The colour is indistinct, but seems to have been a very dark brown. |