. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. MAUSUPIALIA. 2?? arteries; and in the Koala and Wombat the atlas presents only the perforation on each side of the superior arch. In the Perameles and some other Marsupials, as the Cayopollin, an affinity to the cold-blooded Ovipara is mani- fested in the structure of the atlas (Jig. 98), which exhibits a permanent se- paration of the neurapophyses or superior laminae from the centre or body below. In the Koala and Wombat the body tne at^as remains perma- nently cartilaginous, and the lower part of the vertebral ring by
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. MAUSUPIALIA. 2?? arteries; and in the Koala and Wombat the atlas presents only the perforation on each side of the superior arch. In the Perameles and some other Marsupials, as the Cayopollin, an affinity to the cold-blooded Ovipara is mani- fested in the structure of the atlas (Jig. 98), which exhibits a permanent se- paration of the neurapophyses or superior laminae from the centre or body below. In the Koala and Wombat the body tne at^as remains perma- nently cartilaginous, and the lower part of the vertebral ring by dried gristly substance Fig. 98. Atlas of Peru- meles'lagotis, is completed (Jig. 90). In the Petaurists, Kangaroos, Fig. Atlas, axis, and third cervical vertebra, Koala. and Potoroos, the atlas is completed below by an extension of ossification from the neurapophyses into the cartilaginous nucleus representing the body, and the ring of the vertebra is for a long time interrupted by a longitudinal fissure in the middle line, the breadth of which diminishes with age. This fissure is represented in figures of the atlas of a Potoroo and Kangaroo, given by Pander and D'Alton, ( Beutelthiere,Jig. c, plates iii. &vii.); but in some of the skeletons of these Marsu- pials examined by me I find the ring com- pleted and the fissure obliterated. In all the Marsupials the spine of the dentata is well developed both in the vertical and longitudinal directions, but most so in the Virginian and Crab-eating Opossums, (fig. 100), where it increases in thickness posteriorly; in these species also the third, fourth, and fifth cervical vertebrae have their spines remarkably long and thick, but progressively diminishing from the third (Jig. 101), which equals in height and Fig. 100. Fig. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemb
Size: 1620px × 1543px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, booksubjectanatomy, booksubjectphysiology, booksubjectzoology
