Labyrinthodon /rom Warwickshire 537 



If it should be proved that the Lab. pachygnathus, the larger and stronger- 

 awed species, really had bones of the extremities corresponding with those that 

 left the so-termed Cheirotherian impressions, while the impressions of the less ano- 

 malous form more closely agreed with the proportions of the osseous remains of the 

 smaller and weaker species, the difference of the impressions will probably lead to 

 a subgeneric separation. Be that as it may, the evidence that the fossils belong to 

 one and the same natural Batrachian family is not thereby weakened. The pro- 

 gress of palseontological research may expand the application of the term Labyrin- 

 thodon to the family of Sauroid Batrachians; but at present, to avoid an unnecessary 

 multiplication of names, I shall retain it as the generic appellative of the two British 

 species and of the gigantic German Salamandro'ides, whose huge feet might well 

 have fitted the impressions of the ' Cheirotherium Hercules.' 



Labyrinthodon J^geri. 



Lower Jaw. — Two considerable portions of the posterior half of the lower jaw of 

 a large reptile, obtained by Dr. Buckland from the new red sandstone at Guy's Clifl", 

 Warwick, have been referred to in his memoir and in that of Messrs. Murchison and 

 Strickland, on the Warwickshire Sandstones. Both specimens are represented of 

 the natural size in Plate XLVII. ; one (figg. 1, 1*) includes portions of the angular 

 and dentary pieces ; the other (figg. 2 and 3.) is a considerable portion of the 

 angular piece. This specimen exhibits on its outer surface (fig. 2.) the same bold 

 sculpturing and radiated disposition of the grooves and ridges which characterize 

 the bones of the cranium and upper jaw of the Labyrinthodon, figured in PI. XLIII. 

 figs. 1 and 9, and PI. XLVI. fig. 6. But a more important evidence of the affinity 

 of the Guy's Cliff fossil to the previously determined Labyrinthodons is given by the 

 canal on the inner and upper part of the angular piece (PI. XLVII. fig. 3.) for the 

 reception of the dentary element. The specimen which includes part of the dentary 

 piece still more satisfactorily establishes the generic identity of the large reptile of 

 Guy's Cliff with the Labyrinthodon or Mastodonsaurus, by the size, mode of implan- 

 tation, juxtaposition and alternate displacement of the serial teeth (Pi. XLVII. fig. 

 1*). From the analogy of the Labyrinthodon pachygnathus, the laniariform tusks at 

 the anterior part of the jaw must have equalled in size those of the Labyrinthodon 

 JcBgeri, with which gigantic species of Sauroid Batrachian the British species re- 

 presented by the Guy's Cliff fossils is, in my opinion, identical. 



The description and figures of these most interesting fossils in the present me- 

 moir have been taken from plaster casts, which Dr. Buckland had, fortunately, 

 caused to be made : the originals have been mislaid, and have, hitherto, been 

 sought for in vain. Should they be recovered and the structure of the teeth be then 

 examined by microscopic sections, I venture to predict, from the more obvious 



