Notices rt'xpectirig Ne'ju Books. 457 



of their parts we are tempted to confound them with the Ce- 

 tacea or the Fishes ; and it is only by a knowledge extended 

 into the entire of their skeleton that we are enabled to con- 

 vince ourselves of the necessity of classing them with the 

 other I'eptiles. 



It is with those I shall terminate the eighth and concluding 

 part of my book, reserving for consideration in a future work, 

 should my health and occupation permit, the subject of the 

 fossil bones of Fishes. 



LXXIV. Notices respecting Neiv Books. 



Recently/ published. 



THE Third Part of the Philosophical Transactions for 

 1824 has just appeared; with Part I. for the present 

 year. The former contains. 



Observations of the apparent distances and positions of 380 

 double and triple stars,made in the years 1821, 1822, and 1823, 

 and compared with those of other astronomers ; together with 

 an account of such changes as appear to have taken place in 

 them since their first discovery. Also a description of a five- 

 feet equatorial instrument employed in the observations. By 

 John Frederick William Herschel, Esq. F.R.S., and James 

 South, Esq. F.R.S. This paper occupies above 400 pages. 

 Part I. for 1825 contains the following papers : 

 On the effects of temperature on the intensity of magnetic 

 forces ; and on the diurnal variation of the terrestrial magnetic 

 intensity. By Samuel Hunter Christie, Esq. M. A. of Trinity 

 College, Cambridge, Fellow of the Cambridge Philosophical 

 Society : of the Royal Military Academy. Communicated by 

 the President. — The Croonian Lecture : On the existence of 

 nerves in the placenta. By Sir Everard Home, Bart. V.P.R.S. 

 — Observations on the changes the ovum of the frog, under- 



foes during the formation of the tadpole. By Sir Everard 

 lome, Bart. V.P.R.S.— A general method of calculating the 

 angles made by any planes of crystals, and the laws accord- 

 ing to which they are formed. By the Rev. W. Whewell, 

 F.R.S. Fellow of Trinity College, Cambridge.— Explanation 

 of an optical deception in the appeai'ance of the spokes of a 

 wheel seen through vertical apertures. By P. M. Roget, 

 M.D. F.R.S.— On a new photometer, with its application to 

 determine the relative intensities of artificial light, &c. By Wm. 

 Ritchie, A.M. Rector of the Academy at Tain. Communi- 

 cated by the President.— The description of a floating colli- 

 mator. By Captain Henry Kater, F.R.S.— Notice on the 

 Iguanodon, a newly discovered fossil reptile, from tlie sand- 

 Vol. 65. No. 326. June 1825. 3 M stone 



