File:On the anatomy of vertebrates (electronic resource) (1866) (14732488476).jpg

Identifier: b20416039_001 (find matches)
Title: On the anatomy of vertebrates (electronic resource)
Year: 1866 (1860s)
Authors: Owen, Richard, 1804-1892
Subjects: Anatomy, Comparative Vertebrates Fishes Reptiles Mammals Birds
Publisher: London : Longmans, Green
Contributing Library: Wellcome Library
Digitizing Sponsor: Wellcome Library

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ebrae of the Amphis-bcena have no neural spine. The lacertian modifications of the atlas and axis1 agree in the 1 xliv. vol. i. pp. 139—149. 60 ANATOMY OF VERTEBRATES. main with those in the Python. In Istiurus the cervical hypa-pc-physes are compressed, distinct, and articulated to the inter-space between their own vertebra and the one in advance. Thecaudal vertebrae are remarkable for the great length of theirneural spines. In the Chameleon the ribs commence at the fourth vertebra,and those of the sixth are articulated by semiossified cartilages tothe sternum, as are the three following pairs ; in the next eightor ten pairs the long and slender cartilages meet and unite to-gether at their extremities. There are two lumbar and threesacral vertebras; the tail is long and prehensile. In theIguana tuherculata twenty-one vertebras, commencing with thefifth, support free ribs, and those of the ninth first join thesternum. § 23. Vertebral column of Chelonia.—This column is most ex- 51
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Skeleton of Emys Europcea. xxxvilii traordinary in those Reptilia to which, in the manifold modifica-tions of the organic framework, has been given a portable abode,in compensation for inferior powers of locomotion and the wantof defensive weapons. ANATOMY OF VERTEBRATES. 61 The expanded thoracic-abdominal case, fig. 51, K, k, intowhich, in most Chelonians, the head, the tail, and the four ex-tremities can be withdrawn, and in some of the species be thereshut up by movable doors closely fitting both the anteriorand posterior apertures — as, e.g., in the box-tortoises (Cino-sternon, Cistudo)—has been the subject of many investigations;and not the least interesting result has been the discoverythat this seemingly special and anomalous superaddition to theordinary vertebrate structure is due, in a great degree to themodification of form and size, and, in a less degree, to achange of relative position, of ordinary elements of the vertebrateskeleton. The natural dwelling-chamber of the

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