LOWER OLD RED SANDSTONE OF SCOTLAND. 347 



sixteen that they should be presented in the symphysis of two 

 of the jaws ; — it was as one chance out of sixty-four that they 

 should be presented in the symphysis of three of the jaws ; 

 — and that the fractured pieces should be retained so exactly 

 in the lines, each of its jaw, while in the ordinary contingen- 

 cies of misplacement they might have been shifted to any part 

 of the stone, or that they should have been all turned round 

 in the same angle, furnished, of course, other and still more 

 formidable sets of chances against the hypothesis of misplace- 

 ment. Nor did it seem legitimate to oppose to these another 

 set of chances, by arguing that the jaws of many thousands 

 of the vertebrata were well known, and that none of them 

 presented a character so anomalous ; seeing that this mode 

 of argument would equally militate against all these possibili- 

 ties of creation, which the earlier anatomists would have re- 

 garded as very anomalous indeed, but which the researches 

 of the palaeontologists have since fully realized. Such a strange 

 combination of parts as occurs in the Ichthyosaurus or Plesio- 

 saurus is scarce less anomalous, measured by what now ex- 

 ists in the vertebral sub-kingdom, than such a structure of 

 jaw as that exemplified in the Coccosteus. Such were some 

 of my reasonings on the subject, and the result has shown 

 that they were not wholly incorrect. But the peculiarity of 

 the jaws of this ancient fish being now determined on surer 

 grounds than can be supplied by any line of mere inference, 

 I leave to the naturalist the consideration of its meaning and 

 value. 



I may be permitted, however, one other remark regardmg 

 this jaw. From the character of its surface on both sides, it 

 seems to have been covered, like jaws of the more modern 

 type, by integuments. It was altogether an internal, not 

 a dermal bone; and is, so far as I know, the oldest internal 

 bone that has yet presented its structure to the microscope. 

 And it is surely not uninteresting to see the osseous substance, 



