172 AIR-BREATHERS OF THE COAL PERIOD. 



ossified, bi-concave, and with, well-developed spinous processes. The 

 ribs are long and curved ; and there are traces of numerous acces- 

 sory pieces which have been attached to their extremities. The 

 pelvis is of large size and remarkable form ; the ilium long and 

 ■expanded below ; the ischium greatly expanded ; the pubis ex- 

 panded and triangular where it joins the ischium, and round and 

 arched toward the symphysis. The femur is thick and nearly 

 straight, the tibia short and stout, the fibula slender, the phalan- 

 ges broad. The hind limb thus largely developed must have been 

 capable of supporting the whole weight of the body in standing or 

 leaping. The anterior extremities appear to have been compara- 

 tively slender, with thin and long fingers. A few scattered verte- 

 brae lying posteriorly to the pelvis, may perhaps be remains of a 

 tail. There was a dermal covering of small ovate bony scales, of 

 which, however, only a few scattered specimens remain. This 

 species is evidently quite remote from the ganocephalous and laby- 

 rinthodont types of batrachians, and in many respects approaches 

 to lacertians. It may perhaps be allied to the Telerpeton of Elgin, 

 but does not appear to resemble any reptile hitherto found in the 

 coal-formation." 



It is evident, from the remains thus described, that we have in 

 Hylonomus Lyelli an animal of lacertian form, with large and 

 -stout hind limbs, and somewhat smaller fore limbs, capable of walk- 

 ing and running on land ; and though its vertebrae were imperfectly 

 ossified externally, yet the outer walls were sufficiently strong, and 

 their articulation sufficiently firm, to have enabled the creature to 

 erect itself on its hind limbs, or to leap. They were certainly pro- 

 portionally larger and much more firmly knit than those of Den- 

 drerpeton. Further, the ribs were long and much curved, and im- 

 ply a respiration of a higher character than that of modern 

 batrachians, and consequently a more highly vitalized muscular 

 •system. If to these structural points we add the somewhat rounded 

 skull, indicating a large brain, we have before us a creature which, 

 however puzzling in its affinities when anatomically considered, is 

 clearly not to be ranked as low in the scale of creation as modern 

 tailed batrachians, or even as the frogs and toads. We must add 

 to these also, as important points of difference, the bony scales 

 with which it was armed below, and the ornate apparatus of horny 

 appendages, with which it was clad above. These last, as described 

 injhe last section , and illustrated in Plate IV., shew that this little 

 animal was not a squalid, slimy dweller in mud, like Menobranchus 



