22© Astronomical Society. 



cate, not the mammiferous nature of the animal, but the compound 

 form of the crowns of the teeth. 



2. With respect to the most prominent characters by which the 

 Stonesfield fossils are distinguished from recent mammals of the 

 insectivorous and marsupial families, Mr. Ogilby mentioned, first, 

 the position of the condyle, which is placed in the fossil jaws in a line 

 rather below the level of the crowns of the teeth ; and he stated 

 that the condyle not being elevated above the line in the Dasyurus 

 Ursmus and Thylacinus Harrisii, is not a valid argument, because 

 those marsupials are carnivorous. The 2nd point urged by the 

 author against the opinion, that the fossils belonged to insectivorous 

 or marsupial mammifers, is in the nature and arrangement of 

 the teeth. The number of the molars, he conceives, is a second- 

 ary consideration ; but he is convinced that they cannot be separated 

 in the fossil jaws into true and false, as in mammalia ; the great 

 length of the fangs, equal to at least three times the depth of the 

 crowns, he conceives, is a strong objection to the fossils being placed 

 in that class, as it is a character altogether peculiar and unexampled 

 among mammals ; the fox'm of the teeth also, he stated, cannot be 

 justly compared to that of any known species of marsupial or insec- 

 tivorous mammifer, being, in the author's opinion, simply tricuspid, 

 and without any appearance of interior lobes. As to the canines 

 and incisors, Mr. Ogilby said, that the tooth in D. Bucklandii, 

 "which has been called a canine, is not larger than some of the pre- 

 sumed incisors, and that all of them are so widely separated as to 

 occupy full five-twelfths of the entire dental line, whilst in the 

 Dasyurus viverrinus, and other species of insectivorous marsupials, 

 they occupy one-fifth part of the same space. Their being arranged 

 longitudinally in the same line with the molars, he conceives, is 

 another objection, because, among all mammals, the incisors occupy 

 the front of the jaw, and stand at right angles to the line of the 

 molars. "With respect to the supposed compound structure of the 

 jaw, Mr. Ogilby offered no formal opinion, but contented himself 

 with simply stating the appearances ; he, nevertheless, objected to 

 the grooves being considered the impression of blood vessels, though 

 he admitted that the form of the jaws is altogether different from 

 that of any known reptile or fish. 



From a due consideration of the whole of the evidence, Mr. 

 Ogilby stated, in conclusion, that the fossils present so many import- 

 ant and distinctive characters in common with mammals on the 

 one hand, and cold-blooded animals on the other, that he does not 

 think naturalists are justified at present in pronouncing definitively 

 to which class the fossils really belong. 



ASTRONOMICAL SOCIETY. 

 Dec. 14, 1838. — The following communications were read: — 

 I. Extract of a letter from Professor Bessel to Sir J. Herschel, 

 Bart., dated Konigsberg, Nov. 4, 1838*. 



* Prof. Bessel's letter on the parallax of a Cygni, to which the above ex- 



