Coal; its history and uses . ove all things rapidity in themovement of its jaws, has the condyle at the very end ofthe lower jaw, and loses whatever mechanical advantagemay be due to the post-articular process. It gains intime what it loses in force. The accompanying illustration (fig. 20) shows somedetails of the skull of Loxomma,—the mucous grooves 124 COAL. upon the face, which occur in most Labyrinthodonts, butvary much in pattern and degree of development; theexternal nostrils; the large and irregular orbits, which,as in recent Crocodiles, no doubt lodged muscles, glands,and other soft ti
Coal; its history and uses . ove all things rapidity in themovement of its jaws, has the condyle at the very end ofthe lower jaw, and loses whatever mechanical advantagemay be due to the post-articular process. It gains intime what it loses in force. The accompanying illustration (fig. 20) shows somedetails of the skull of Loxomma,—the mucous grooves 124 COAL. upon the face, which occur in most Labyrinthodonts, butvary much in pattern and degree of development; theexternal nostrils; the large and irregular orbits, which,as in recent Crocodiles, no doubt lodged muscles, glands,and other soft tissues, besides the eye-balls themselves;and the two small rounded occipital condyles. Loxommahas well-ossified biconcave vertebrse, and long ribs withtwo articular cups. The other parts of the body are notknown for certain. In size it far surpassed Archegosaurus,but fell nearly as far short of Mastodonsaurus, at anyrate in the dimensions of the sliull. If something likethe same proportion obtained between the skull and the. Fig. 20. Skull of Loxomma. total length as in the recent Gavial, Loxomma must havebeen as much as fourteen feet long. Another Labyrinthodojit of special interest is Urocor-dylus, first described by Prof. Huxley from remains foundin the Kilkenny coal-field. TJrocordylus is distinguishedby the great length and vertical depth of its tail, which CHAP. IV. ANIMALS OF THE COAL MEASURES. \25 far exceeds the rest of the body in both of these dimen-sions. Each of the very numerous caudal vertebrae passesupwards and downwards into a wedge-shaped spine orprocess, which is flattened from side to side. The apexof the spine is united to the vertebra, the free edge isslightly notched, and the height is in most about twicethe extreme breadth. It will be seen at once that caudalvertebrge of this form and to the number of seventy-five(there are but twenty in the trunk) represent a powerfulswimming organ. Urocordylus is the most speciallyaquatic of the known Labyrinthodonts.
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Keywords: ., bookcentury1800, bookdecade1870, bookpublisherlo, booksubjectcoal
