456 



nated by claws. The author distinguishes two principal varieties of 

 the adult animal ; the one remarkable for the great length of the 

 abdomen and roundness of the caudal extremity ; whilst the other is 

 characterized by greater compactness of form, a shorter abdomen, 

 and more pointed tail. The first variety was found to measure, in 

 length, from the one-lOOth to the 45th, and the second, from the 

 one-160th to the 109th part of an inch. 



The author gives a minute description of the ova of these entozoa, 

 which he follows in the successive stages of their developement. 

 The paper is accompanied by numerous drawings of the objects de- 

 scribed. 



2. " On Factorial Expressions, and the Summation of Algebraic 

 Series." By W. Tate, Esq. Communicated by the Rev. Henry 

 Moseley, M.A., F.R.S., <Src. 



This paper, which is wholly analytical, contains an investigation of 

 certain general methods for the summation of algebraic series, which 

 have led the author to the discovery of some curious and elegant pro- 

 positions relative to factorials and the decomposition of fractions ; 

 and also to a new demonstration of Taylor's theorem. 



3. " Notice of the Comet ;" in a Letter from Captain John Grover, 

 F.R.S., addressed to P. M. Roget, M.D., Sec. R.S., and dated from 

 Pisa, March 21st, 184-3. 



The author states that at Pisa, on Friday, the 17th of March, 1843, 

 at eight o'clock in the evening, he saw a luminous arc in the heavens, 

 extending from a spot about a degree to the south of Rigel to some 

 clouds which bounded the western horizon. It was about 40 minutes 

 in width ; the edges sharply and clearly defined. On the 20th of 

 March, the author could distinctly trace the extremity of the lumi- 

 nous streak, which he concluded was the tail of a comet, below the 

 lower part of the constellation Orion, and reaching to the star Eri- 

 dani ; while the stars 3 and e Eridani were distinctly seen with the 

 naked eye through the coma. From rj Eridani, it extended 47° 30' 

 to a spot nearly equidistant from ^ Orionis and r] Leporis. 



4. Variation de la Declinaison et Intensite Horizontales Mag- 

 netiques observees a Milan pendant vingt-quatre heures consecu- 

 tives le 18 et 19 Janvier, et le 20 et 25 Fevrier 1843." Par C. Carlini, 

 For. Mem. R.S. 



5. A paper was also in part read, entitled " On the general and 

 minute Structure of the Spleen in Man and other Animals." By 

 William Julian Evans, M.D. Communicated by P. M. Roget, M.D., 

 Sec. R.S. 



