Elements of comparative anatomy (1878) Elements of comparative anatomy elementsofcompar00gege Year: 1878 MBS OF VERTEBRA! A. 4 tl Crocodilini. These processes are not laid down in cartilage, but arc secondaiy ossifications. The lumbar portion of the vertebral column, which is fused with the sacrum, has no ribs in Birds, but distinct rudiments may be seen on the true sacral vertebras, so that even here the ilium is not united directly to the vertebras, but to the rudimentary ribs that are attached to them. Similar rudiments may be made out in the Crocodilini. When the caudal region is well dev
Elements of comparative anatomy (1878) Elements of comparative anatomy elementsofcompar00gege Year: 1878 MBS OF VERTEBRA! A. 4 tl Crocodilini. These processes are not laid down in cartilage, but arc secondaiy ossifications. The lumbar portion of the vertebral column, which is fused with the sacrum, has no ribs in Birds, but distinct rudiments may be seen on the true sacral vertebras, so that even here the ilium is not united directly to the vertebras, but to the rudimentary ribs that are attached to them. Similar rudiments may be made out in the Crocodilini. When the caudal region is well developed, the same structures as those which have been already alluded to as rudimentary ribs may be seen to enclose the caudal canal. With regard to the connection between the ribs and the vertebras ; in the Saurii, Crocodilini, and Aves, there are generally two points of attachment, for the rib is articulated to the centrum by a capitulum (/3), and to the transverse process by a tubercle (a). Tho posterior ribs gradually get to have only one point of attachment. In the Mammalia the cervical ribs have passed completely into the vertebras, and it is only now and again that we meet with a free rib. The thoracic ribs, which vary in number, arc divided into the two above- mentioned pieces, and so show that ossi- fication has not equally affected the whole rib, but that a sternal portion remains in its cartilaginous condition. When this portion is ossified (Edentata, Cetacea) it forms a separate piece; in Ornithorhyn- Thoracic vertebra of elms, it is again divided in the case of Buteo vulgaris, c Centrum the last five ribs; this happens also in of the vertebra. s Superior -iir • spinous process, tr Transverse JUaillS. ^ ^ process. ioEib. a Tuberculum. The anterior ribs alone reach to the /3 Capitulum. sternum. The hinder ones are either connected with the sternal end of the one next in front, or project freely, and so get to resemble the rudimentary forms, to which class of
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