for the Ascidian Polypes. 353 



tliis papei'j it is at least three months later than that of Mr. J. V. 

 Thompson. This^ however, appears to me a mode of stating the 

 jioint far too favourable to Ehrenberg. From the prefix above 

 quoted, and still more from intrinsic evidence, it is clear that 

 puL't at least, and probably a very great part of the paper as it 

 naw appears, was not written till 1833, as it was certainly not 

 [jiiblished in a complete state till after February 1834. From 

 the paper itself it is impossible to say what part was read in 

 J '-31, and what added or altered afterwards; and I cannot avoid 

 the remark, that it appears not a little discreditable to the pub- 

 lishing management of the Berlin Academy, that such a con- 

 I'usion of dates should be allowed to exist in memoirs published 

 under their direction. The fact is, that with respect not only to 

 this paper, but also to a second by Ehrenberg in the same 

 vdkime of Reports*, which was read on the 22nd of INIarch 1832, 

 biit not "revidirt mid gedruckt^' till February 1834, as no 

 means exist by which it can be determined what part was really 

 read at the times specified, and what subsequently added or 

 altered, the only just and safe way of applying them in questions 

 of date would be to take that of their final and real publication, 

 viz. 1834. 



2. With respect to ' Symbolse Physica?,' no difficulty whatever 

 exists in our assigning the date of 1831 to the Part with which 

 we are here concerned, viz. that containing the " Animalia ever- 

 tebrata, cxclusis Insectis.^^ For in the first place, that is the 

 date given to it upon the cover in which it is stitched ; and in the 

 second place, Ehrenberg himself in the former paper above referred 

 to, p. 254, gives the date of that Part of ' Symbolse Physicse ' as 

 June 1831. Moreover, though the further citation of evidence 

 is supererogatory, in the commencement of the same paper read 

 March 3, 1831, lie styles it a precursor "Vorlaufer," to the 

 further details which he intended to give in ' Symbolse Phy- 

 sicse ' ; and again in the latter work itself, be adverts to the above 

 paper as having been read before the Academy " some months 

 pi-eviously,^' " abhinc aliquot menses." 



With reference to the other portions of * Symbols Physicse,' 

 (leaving out of the question that or those containing the Insects, 

 by Klug) as they are not concerned in the present inquiry, I would 

 merely remark, that in them, as in the papers read before the 

 Berlin Academy, such a confusion of dates appears to exist, that 

 notwithstanding the title-page and preface, both of which are 

 dated 1828, it would seem from intrinsic evidence that a consi- 



&c. 



* " Ueber die Natur iind Bildung der Corallenbauke des Rothen Meeres," 

 Ann. ^^ Mag. N. Hist. Ser. 2. Vol. x. 23 



