293 Geological Society. 



elites go still further ; for, on submitting to the microscope of 

 Professor Owen some teeth similar in outline to those of his genus 

 Dendrodus, he discovered in them precisely the same dendridic 

 disposition of the vascular canals as tliat which led liim to establish 

 the genus from Scottish fossils. Nor does the value of this appli- 

 cation of the microscope stop here, for Professor Agassiz has in- 

 formed me, that availing himself of the weapons which Professor 

 Owen had so skilfully wielded, he has commenced a series of re- 

 searches, not only into the teeth but also into tlie structure of all 

 the hard enamelled bones of the Russian fossil fishes, by which he 

 will be able to show the same distinction in the other bones of the 

 genera of this class, which Professor Owen has successfully esta- 

 blished in relation to the hard parts of the higher order of animals. 

 In such hands, therefore, tlie microscope has become an instrument 

 of great utility in identifying fragments apparently obscure ; and, as 

 it has been applied to the sliells of MoUusca, and even to the lowest 

 links in animal life, as well as to fossil plants, the geologist has thus ac- 

 quired a new and powerful auxiliary. I am here, however, treading 

 on ground now fortunately occupied by the Microscopical Society, 

 the active promoters of -whicli arc well entitled to our gratitude. 



Mijhdon. — One of the most brilliant, and, I venture to say, not 

 the least durable of the researches in palaeontology, remains to be 

 mentioned in the description of the Mylodon robustus, a new species 

 of gigantic edentate animal, accompanied by observations on the 

 affinities and habits of all Megatherioid animals. After a sketch 

 of the labours of Cuvier, who first described the huge Megatherium 

 and pointed out its analogy to the family of Sloths and Armadillos, 

 of the succeeding writings of Jefferson and Harlan upon the genus 

 Megalonyx, of Di\ Lund on the Coelodon and Sphenodon of Brazil, 

 and of his own researches which established the Mylodon and Sce- 

 lidotherium, Professor Owen proceeds to describe the megatherioid 

 animal which he has named Mylodon robtistns. 



Of the purely anatomical descriptions, it is not my province to 

 speak, and referring you to the Avork in which, through the en- 

 lightened munificence of the College of Surgeons, all the necessary 

 illustrations have appeared, I pass to the generalizations, and learn 

 that the Mylodon, in common with the Alegatherium and Megalo- 

 nyx, are genera of the family of Gravigrada, as distinguished from 

 the Tardigrada in the order Bruta. 



Professor Owen then proceeds to a comparison of the anatomy of 

 the Mylodon with that of all analogous creatures, and after an able 

 analysis, he satisfies himself, and also, I am persuaded, every one 

 who has followed his close reasoning, that he has at length ascer- 

 tained the true habits and food of this family of mammifers. From 

 their dentition, it is inferred that the ^Megatherium and Mylodon must 

 have been phyllophagous, or leaf-eating animals ; whilst, from 

 their short necks, the very opposite extreme to the camelopard, 

 they never could have reached the tops of even the lowest trees. 

 Cuvier, on the contrary, suggested that they were fossorial, or dig- 



