BY MBS MILLEB. IjL 



marked * * which describes the true nature of the vertebral 

 anatomy of Coccosteus. The other paper was read to the 

 geological section of the British Association at Edinburgh in 

 1849. As only a short abstract of the latter is given in the 

 volume of the Association, it ought by all means to be printed 

 in full in your new volume ; the more so that it is in itself a 

 kind of supplement to the "Foot-prints." As specimens 

 are frequently alluded to, and as woodcuts to such an extent 

 would be very expensive, it would suffice to state in a note 

 that the specimens described are now in the Museum of the 

 University." These suggestions have been attended to, and 

 I merely quote from the letter to show the source from 

 which they are derived. 



These remarks by the author of the " Foot-prints" on the 

 structural peculiarities of the earlier ganoids embrace, as 

 the reader will perceive, both the placo and the lepido-ga- 

 noids of Owen, — a distinction which the author had not 

 learnt to make, and to which we cannot, of course, now tell 

 how far he would have adhered. But the value of the 

 close and minute observations remain the same, and the more 

 so as it is happily almost confined to structure, and only 

 incidentally glances at the relations of place or position. 

 Hereby the alterations in relative position only impart ad- 

 ditional value to the observations, as enhancing the import- 

 ance of the subject. Members of the great ganoid order 

 of Agassiz have, as we have said, been found in the Upper 

 Ludlow bed, accompanying the placoids, and likewise many 

 hundred feet below it, as yet unaccompanied by other ichthyic 

 remains. The same remarkable family passes upwards through 

 the transition beds, and finds an ample development in the 



