Microscopical Society. G5 



thirty-nine original members of the Society, it having been deter- 

 mined that those who joined the Society on or before the first night 

 of meeting should be considered original members. 



Mr. Owen communicated a paper on the application of Microsco- 

 pic examinations of the structure of teeth to the determination of 

 fossil remains. After alluding to the essential service rendered by 

 the microscope to the chemist, mineralogist, and vegetable physio- 

 logist, he proceeded to offer a few examples of the utility of the 

 microscope to the geologist, when applied to the investigation of 

 the structure of fossilized teeth. 



The first example adduced was that of the Saurocephalus, an 

 American fossil animal which had been referred to the class of rep- 

 tiles. After pointing out the destructive characters of the micro- 

 scopic texture of the teeth in reptiles and fishes, it was shown that 

 the Saurocephalus, according to this test, unquestionably belonged 

 to the latter class, and that it most closely resembled Sphyrsena 

 among recent fishes in its dental structure. 



The second instance was the Basilosaurus of Dr. Harlan, which 

 had been referred to the class Reptilia ; and the double-fanged struc- 

 ture of its teeth, had, on the strength of its supposed Saurian affi- 

 nities, been adduced to weaken the arguments advanced in favour of 

 the mammiferous nature of certain fossils from the Stonesfield oolite. 

 Mr. Owen, after describing the microscopic character of the teeth of 

 the Basilosaurus, showed that it deviated from the Saurian structure 

 in this respect as widely as the Saurocephalus, but that the modifi- 

 cation of its dental structure resembled most closely that of the 

 cachalot and herbivorous Cetacea. Lastly, Mr. Owen alluded to the 

 difference in the views entertained by Cuvier and M. de Blainville, as 

 to the affinities of the megatherium, which was referred by the one to 

 the family of the Sloths, and by the other to that of the Armadillos: 

 after explaining the well-marked differences in the microscopic cha- 

 racters of the dental structure in these two families of the so-called 

 Edentata, Mr. Owen proceeded to describe the structure of the 

 teeth of the megatherium, and to show that in its close resemblance 

 to the dental structure of the sloths, it confirmed the views of the 

 great founder of the science of fossil remains. This paper was ac- 

 companied by a number of very beautiful illustrative drawings, ex- 

 hibitins: the minute structure of the teeth of the animals referred to. 



Mr. Jackson then read a short paper drawing the attention of the 

 Society to a mode of mounting the compound microscope, w-hich 

 differs in some particulars from the methods generally adopted. 

 The principal object to be kept in view in the construction of the 



Ann. Nat. Hist. Vol.5. No. 28. March \ 840. f 



