the Organization and Reproduction of the Polythalamia. 311 



each other, in one genus. I think it is clear from this that 

 Ehrenberg^s correction, that I should have indicated the Cornu- 

 spirce questionably as young Agathistegia, and not as a new genus, 

 is destitute of all foundation, and that the addition, *'But — they 

 increased his Monothalamia !" (which would lead the reader to 

 suspect that, for the sake of a preconceived opinion, I would 

 have forced nature) throws no very favourable light upon the 

 love of truth of its originator. 



The irritated frame of mind in which Ehrenberg evidently 

 opposes the entire division of Monothalamia established by me 

 is further distinctly expressed in a remark attached to a quota- 

 tion from my book at p. 332 of the ' Monatsberichte ^ for the 

 year 1858. It commences thus : — " I can only repeat my regret 

 that in this work the Difflugice and Arcellce of the Polygastrica 

 are confounded with the Polythalamia ; and every physiological 

 base for a systematic arrangement of the allied forms is thereby 

 set, not in progress but in contradiction [sic !). In it, moreover, 

 the name Miliulida has again received a new application to 

 which it has no right, as, with D'Orbigny, it only indicates one 

 section of the Agathistegia in question : and as regards M. 

 Schultze's Monothalamia, his representation leaves it wholly 

 unproved that, after the deduction of the Polygastrica, they 

 are not all young of the other Polythalamia — especially as the 

 mode of reproduction of none of these forms is placed beyond 

 doubt, and it is expressly stated that some are not to be distin- 

 guished from the young of others." 



Although Ehrenberg will certainly not be able to establish 

 his opinion of the necessity of a separation of the Arcellce and 

 DiffiugicE, as Polygastrica, from Gromia, Lagynis, Euglypha, and 

 other Rhizopoda included by me in the family Lagynida, and 

 even the Cornuspiridce must be allowed to stand untouched, I 

 may perhaps afford him a certain feeling of satisfaction by ad- 

 ducing the following interesting fact with regard to one family 

 of Monothalamia. The Orbulinidce, including the single genus 

 Orbulina, will probably have to be suppressed, — not, however, 

 because the Orbidina have been recognized, as Ehrenberg pro- 

 phesied, as the young of Polythalamia. Recent observations 

 prove that Orbidina is a separated and independently subsisting 

 chamber of a Globigerina. The first observations relating to 

 this were made by Pourtales, and published in ' Silliman's 

 American Journal,^ vol. xxvi. p. 96 (reprinted in the ' Annals 

 and Magazine of Natural History,^ 1858, vol. ii. p. 235). After 

 calling attention to the great similarity (previously observed by 

 others) in the structure of the shells of Orbulina and Globi- 

 gerina, the above-mentioned naturalist reports that in deep-sea 

 soundings (which, as is well known, contain Polythalamia of the 



