Bibliographical Notices. 391 



that two colonies may attach themselves to each other to form 

 a larger confederation, after what has been said as to the 

 facility with which the members of the same chapel married 

 and divorced each other. 



Here the observations close. 



Is the mode of reproduction (fissiparity) which I have just 

 described the only one possessed by this species? This is a 

 question which I cannot venture to decide ; we must not 

 hypothecate the future ; and if it is true that we do not know 

 any other mode of propagation than the above in certain 

 genera (Protamoeba, Myxodictyum), it is not less true that 

 our ignorance in this respect may merely be the consequence 

 of adverse circumstances. We may, however, note that in the 

 Monera which encyst themselves for the purpose of propaga- 

 tion ( Vamjiyrella, Protomyxa, &c.) we rarely find that the 

 species is also endowed with active fissiparity during the 

 period of its free existence; and this consideration may lead us 

 to assume that we have to do here with a simple organism 

 having only the simplest and most rudimentary of all the 

 modes of multiplication, division without any preliminaries in 

 the free state. 



After what has just been stated it can hardly be doubted 

 that our Monobia confluens is a Moneron. Is it possible that 

 we have to do with an evolutive phase of a higher organism ? 

 I see no reason to suppose any thing of the kind ; and analogy 

 is opposed to such a suspicion. 



Like Myxodictyum sociale, this Moneron might be regarded, 

 after the example of Claus, as a naked Foraminifer, if we did 

 not know that the latest investigations on the Foraminifera 

 tend to demonstrate the general existence of a nucleus in the 

 representatives of that group. It therefore seems tome neces- 

 sary to retain the order Monera as Hackel established it, 

 until our knowledge of the mutual relations of the Protozoa 

 shall become more complete. 



BIBLIOGRAPHICAL NOTICES. 



On the Structure and Affinities of the " Tabidate Corals " of the 

 Palaeozoic Period, with Critical Descriptions of Illustrative Species. 

 By H. Alleyne Nicholson, M.D., D.Sc, F.L.S., &c. W. Black- 

 wood & Sons : Edinburgh & London, 1879. 



This work is a further contribution towards the history of the 

 Tabulate Corals, and contains a record of researches carried on during 

 some years past on the Palaeozoic species. The study of the forma 



