170 LIFE OF BENJAMIN SILLIMAN. 



namely, a single bone or articular facet of a bone on 

 which Cuvier deemed it possible to reconstruct the entire 

 animal, is inadequate to that end. In this opinion I do not 

 coincide. I have had too frequent evidence of the potency 

 of the law of correlation of structures in an animal organ- 

 ism to doubt the strength of Cuvier's proposition. But if 

 a single bone has been deemed insufficient to give the en- 

 tire animal, with more reason may we doubt the efficacy of 

 a footprint. We must bear in mind the conflicting opinions 

 to which the Chirotherian impressions have given rise ; next, 

 in regard to the Ornithicnites, it is important to remember 

 that there were reptiles at the age of the New Red Sand- 

 stone, the Rhynchosaurus, e. g., (see " Transactions of the 

 Cambridge Philosophical Society," Vol. VIL, Part iii., p. 

 355,) which presented a singularly close approximation to 

 birds in the form and structure of their edentulous skull ; 

 and might not a corresponding modification of the feet 

 complete the resemblance of these ancient reptiles to the 

 fabled cockatrice ? A biped reptile would not be more 

 anomalous than a jerboa or kangaroo. In the foregoing 

 remarks I wish to be understood as merely indicating the 

 grounds which justify caution in assuming the existence of 

 a highly organized, warm-blooded, quick-breathing, perhaps 

 volant, feathered biped, from footprints merely. I have, 

 however, recently acquired very important additional evi- 

 dence of the former existence, in the Island of New Zea- 

 land, of a gigantic bird, having the same low grade of 

 organization as regards the respiratory system which I have 

 demonstrated in the Apteryx of the same island (" Zoologi- 

 cal Translations," Vol. I.). It is to this circumstance, per- 

 haps, that Dr. Daubeny alludes in his letter to you. -My 

 evidence is not, however, footprints, but the bones them- 

 selves. If you will refer to the " Transactions of the Zo- 

 ological Society," Vol. III. Part i. p. 29, you will see the first 

 indication of the gigantic struthious bird of New Zealand, 

 which vindicates Cuvier's principle, as showing what may 



