472 Royal Astronomical Society. 



Nasmyth as follows j and, he says, they would certainly indicate a di- 

 stinct species of Mastodontoid animal : — 



1. The great extent of the crusta petrosa. 2. The close aggre- 

 gation of its corpuscules. 3. The granulated structure of these cor- 

 puscules. 4. The coarse granulated structure of the compartments 

 of the radiating fibres. 5. The close parallel perpendicular arrange- 

 ment of the fibres of the crusta petrosa. 6. The irregular congeries 

 of granules surrounding the fibres of the ivory. 7. The peculiar tor- 

 tuous appearance occasionally exhibited by these fibres. 



On the whole, Mr. Nasmyth observes, the several species of ani- 

 mals noticed in his paper seem to be nearly allied, and fitted to 

 exist under nearly similar conditions ; and though the early aeras to 

 which these Pachyderms must be referred, present, he says, consider- 

 able uniformity of circumstance, yet they must have demanded some 

 variety of detail in the animal organization. 



Finally, the characteristics in the minute structure of the tusks of 

 all the five animals betray, the author observes, greater varieties than 

 are found to exist even betwixt some genera possessed of tusks ; and 

 if it be established that specific differences positively do exist among 

 all these animals, then the value of this kind of observation is great; 

 but if the five animals are all to be grouped in one category, then this 

 mode of observation is of no value in palaeontological researches. 



ROYAL ASTRONOMICAL SOCIETY. 

 [Continued from page 314.] 



June 9. (Communications respecting the Comet continued.) — ■ 

 15. Letter from Professor Kendall, containing Observations of the 

 Comet made at Philadelphia. Communicated by Lieut. -Col. Sabine. 



Philadelphia, April 27, 1843. 



Sir, — I send you the result of the observations of the great comet 

 of February 1843, made by Mr. Walker and myself with the Fraun- 

 hofer equatoreal, at the Observatory of the Central High School, lati- 

 tude 39° 57' 8", longitude 5 h m 41 s> 9 west of Greenwich. The mea- 

 sures were all made with the Fraunhofer filarmicrometer, power 75, 

 except on the 9th and 1 Oth of April, when the extreme faintness of 

 the comet compelled us to use the ring-micrometer. We first saw 

 the nucleus on the 11th of March and brought the comet to the 

 centre of the field, and read the graduations. The place given on that 

 evening is liable to an error of two minutes of space. That of 

 the 10th of April is liable to an error of about one minute of space. 

 Those of the other evenings were the result of satisfactory measures. 

 The nucleus on the 1.1th of March was near the star £ Ceti, of the 

 third magnitude, and was of about the same brightness. The tail 

 extended between Rigel and Sirius, about 1° south of its position 

 on the 18th, when we saw it and also the nucleus, but made no 

 measures. In the comet-searcher the nucleus appeared on the 11th, 

 with a well-defined disc, larger than that of Jupiter in the same in- 

 strument. In the 9-feet equatoreal it had no appearance of a disc, 

 but only of a nebulosity gradually condensed toward the centre ; so 

 that it was impossible to distinguish any nucleus. I have no doubt 

 that this comet was seen in the day-time, on the 28th of February 



