OCR Text |
Show 1875.] MR. A. II. GARROD ON HALMATURUS LUCTUOSUS. 55 it is, however, much smaller and narrower than in Macropus; as in that genus, it is more marked in the mandibular than in the maxillary molars. The peculiar twist in the molar-premolar series of the lower jaw (the anterior teeth turning outwards and the posterior inwards), by which the trenchant edges are rendered parallel as in the upper jaw, at the same time that the rami of the mandible converge, is, as might be expected from the previously mentioned greater parallelism in the maxillary series of Dorcopsis, more marked in that genus than in Macropus. It may be mentioned that the molar teeth in Dorcopsis and Dendrolagus do not exhibit any characters intermediate between Macropus aud Hypsiprymnus. The remaining bones of the skeleton do not present features of special interest. The typical number of precaudal vertebrae are present, namely C. 7, D. 13, L. 6, and S. 2 ; there are 19 caudal vertebrce, with well developed chevron bones between the proximal ones. The anterior arch of the atlas presents no gap, the two moieties meeting with a linear junction. The anticlinal vertebrae are the 10th, 11th, and 12th dorsal. The clavicles are fairly developed; and the first ribs are very broad. There is a supracondyloid foramen to the humerus ; and the fibula is not ossified to the tibia. The following are the lengths of some of the most important long bones :-Humerus 2*75 inches, radius 3-2, femur 5*1, tibia 6*2, fourth metatarsal 1*8, pubic symphysis 1*7. Respecting the soft parts, the tongue has three small circumvallate papillae at its base, arranged in the ordinary V-shaped manner. The palate presents several strongly marked transverse ridges. The submaxillary and sublingual glands are small, the former ellipsoid in shape. The parotids are large, flat, and triangular, with their bases directed towards the root of the neck, and their apices to the masseter muscle. Their position is indicated by the dotted lines in Plate VIII. The left lung is formed of a single lobe, wi£h a slight fissure on the ventral margin, near the apex, opposite the broadest part of the heart. The right lung consists of two lobes, the main portion and the azygos lobe. The lobe proper presents two fissures-one near the apex, running vertebrally and diaphragmatically, separating an apical lobule, the other running vertebro-apically and marking off the median lobule*. This median lobule partly embraces the base of the heart, as in many animals. There is no third bronchus. The heart is quite Macropine, there being two superior venae cavae. The right ventricle also spirally wraps round the much stronger left, as in Macropus. The stomach is perfectly Macropine ; that is, it is elongated, sacculated, with the oesophagus entering it much nearer the caecal than * The method of description here adopted is an attempt to ayoid the employment of terms which necessitate any assumption with respect to the position of the animal. Supposing the animal to have its vertebral column horizontal, and iIs four limbs on the ground, then the above description might be thus read:- -'The lobe proper presents two fissures-one near the apex, running upwards and backwards, the other running forwards and upwards." |