. On the anatomy of vertebrates. Vertebrates; Anatomy, Comparative; 1866. 182 ANATOJIY OF VERTEBRATES. Ijasis, 64, for muscular attachments, became co-expanded ; the ischia also, 63, assumed the form of flattened triangular plates; and the ilia, though still ' long bones,' were stronger, and attached by ligament to the riblets of one or two vertebra3; and these, in Nothosaurus, became expanded for more effective fixation of the pelvic arch. A ' tarsus,' 68, and ' metatarsus,' are now definable ; and the ' digits,' with fewer joints, do not exceed five in number. All the bones are solid in both
. On the anatomy of vertebrates. Vertebrates; Anatomy, Comparative; 1866. 182 ANATOJIY OF VERTEBRATES. Ijasis, 64, for muscular attachments, became co-expanded ; the ischia also, 63, assumed the form of flattened triangular plates; and the ilia, though still ' long bones,' were stronger, and attached by ligament to the riblets of one or two vertebra3; and these, in Nothosaurus, became expanded for more effective fixation of the pelvic arch. A ' tarsus,' 68, and ' metatarsus,' are now definable ; and the ' digits,' with fewer joints, do not exceed five in number. All the bones are solid in both IclttJii/o- and Sauro-pterygia. From the Sauropterygian type of pelvic arch and limb, the transition is easiest to that in the marine Chelurda of the j^resent day. But the course of developement from the Proteus will Jae here resumed and traced to the saltatory grade which the hind- limlj acquires in the Batrachian order. Amplduma tridactylum, with proportionally shorter hind-limbs than in Protevis (fig. 101, d), has them terminated by three toes. Menohranchus shows four toes : and Menopoma five, which is the numljcr usual in the hind-limbs of Newts and Salamanders. In Mmopoina, fig. 43, the sacral vertebra, ,?, has a longer and stronger transverse process, t, and riblet, pjh than the vertebras before and behind ; and pi is united to the cartilaginous elements, 63 and 64, closing the inverted arch by the ri))-like continuation, 62. To the lower end of this simple 'ilium' and conjoined part of the ' ischio-pubic' cartilage is ligamentously attached the short and simple femur. To this succeeds a shorter tibia and fibula — the latter reminding us of the plesiosaurian fibula, by its outward curve. The tarsus is cartilaginous in Menopoma; the metatarsals support 1, 2, 3, 3, 2 phalanges, resj)ectively, from the innermost, I, to the fifth, V. The toes are webbed to near the last joint. Every joint in the limb is syndcsmotic, and the ossification of the bones is limited to an outer
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Keywords: ., bookauthorowenrichard18041892, bookcentury1800, bookdecade1860
