File:Animal and vegetable physiology, considered with reference to natural theology (1836) (14784629193).jpg

Identifier: animalvegetable01roge (find matches)
Title: Animal and vegetable physiology, considered with reference to natural theology
Year: 1836 (1830s)
Authors: Roget, Peter Mark, 1779-1869
Subjects: Biology Physiology Plant physiology Natural theology
Publisher: Philadelphia, Carey, Lea & Blanchard
Contributing Library: NCSU Libraries
Digitizing Sponsor: NCSU Libraries

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
s, the useof which is to turn the foot outwards, both in stepping and in swimming. 310 THE MECHANICAL FUNCTIONS. tremitles of the salamander make their appearance earlierthan the hind legs, and the tail remains as a permanent partof the structure. The rudimental ribs are exceedingly small,and the sternum continues cartilaginous. The pelvis has noosseous connexion with the spine, but is merely suspendedto it by ligaments. The land salamanders have a roundedtail, but the aquatic species, or Tritons, have it compressedvertically; thus retaining the fish-like form of the tadpole,and the same radiated disposition of the muscles. § 3. Ophidia, In the class of serpents we see exemplified the greatestpossible state of simplicity to which a vertebrated skeletoncan be reduced; for, as may be seen in Fig. 201, whichshows the skeleton of a viper, it consists merely of a length-ened spinal column, with a head but little developed, and aseries of ribs; but apparently destitute of limbs, and of the
Text Appearing After Image:
bones which usually connect those limbs with the trunk;there being neither sternum, nor scapula, nor pelvis.^ In * Professor Mayer has, however, traced obscure rudiments of pelvic bonesin the Unguis fragilis, the Anguis ventralis, and the Typhlops avcotatus,and is of ophiion that they exist much more generally in this order of rep-tiles than lias been commonly imag-ined. Some serpents, as the Boa, Python,Tortryx and Eryx, have claws, which may be considered as rudiments of feet,visible externally. Ln others, as the Jnguis, Typhlops, and Amphisbocna, SERPENTS. 311 the conformation of the skull and bones of the fiice, tlicy pre-sent strong analogies with batrachian reptiles, and also withfishes, one tribe of which, namely, theapodous oranguilliformfishes, they greatly resemble by the length and flexibility ofthe spine. These peculiarities of conformation may be in agreat measure traced to the mode of life for w^hich they aredestined. The food assigned to them is living prey, whichthey m

Note About Images