228 Prof. J. E. Duerden on tlie 



septa are added in tlie same bilateral manner at four distinct 

 regions. 



Witliin the present year, Mr. C. E. Gordon, working in 

 the Palpeontological Laboratory of Columbia University, New 

 York, has published a paper, " Studies on Early Stages in 

 Paleozoic Corals^' (Anier. Journ. Science, vol. xxi. Feb. 1906), 

 devoted almost exclusively to a discussion of my first 

 contribution. By inverting my figures Gordon shows that 

 the sections of Lophoiihyllum can be brought into harmony 

 with Kuiith^-^ oft-repeated figure representing the schematic 

 septal ])lan of a zaphrentoid coral, a fact of which tiiere 

 could be no possibility of dispute. Further, while admitting 

 the hexameral nature of Lophophyllum , he attempts to show 

 that it docs not re|)resent the true primary character of the 

 liugosa, but is to be explained as a dej^arture from a primary 

 tetramerism, due to acceleration in time of appearance of the 

 tliiid jiair of septa. Moreover, from his own observations on 

 a decalcified silicified specimen of Streptelasma i'>rofundam 

 (Owen), he presents what he considers as evidence in sup]:»ort 

 of a primary tetramerism. He concludes '' that the primitive 

 condition of these [primary] septa in the E-ugosa is not yet 

 settled," and that exception must be taken to my statement 

 that '' studies on the septal development of extinct Palaeozoic 

 corals reveal that in these early >k)rms the primary septal 

 plan was hexameral like that of mocftrn fcrms." 



These assertions of Gordon are so opposed to what I hold 

 to be the truth with regard to the Rngosa that it becomes 

 necessary to re-open the question, Tlie problem is one of 

 greatest importance if we are to arrive at a proper appreciation 

 of the phylogenic relationships of the Rugosa. 



Since tlie apj^earance of my first paper 1 have obtained 

 much additional evidence in su))port of my contentions, 

 and I shall attempt to show that Gordon's assertions are 

 not warranted by the evidence he submits. In the first 

 place, it must be admitted that the iigures of Lopho- 

 phylhim given in U)02 are unsatisfactory, from the fact that 

 the microscopic sections upon which they were founded 

 where not all taken from the same individual coral. 

 Exception might be taken to their representing the actual 

 development of the septa, while the stages depicted are not 

 always those best adapted for illustrating the sequence. In 

 my later investigations I have pursued a different method of 

 study, the results from which are far more reliable than those 

 obtained from the old method of sections. In preparing 

 separate sections much loss of material is entailed, only a few 

 Bcctions can be obtained from any one corallum, and the 



