368 Profs. King and Rownej on 



are really foraminiferal organisms" (p. 159). His position, 

 however, has yet to be proved : nay, we shall at once meet it 

 by the statement that the Stromatoporids do not even belong 

 to the class Rhizopoda — that they are demonstrably sponges *. 

 Therefore, though no objections can be made to the so-called 

 " Strom atoporoid successors of Eozoon " being adduced by way 

 of illustrating the presumed mode of growth of the latter, we 

 decidedly refuse to allow them to be introduced in the manner 

 stated above — that is, as essentials in the controversy. 



Dr. Dawson affirms that the " radiating canals " of Cauno- 

 2)ora 2J^anuIata and Coenostrema (two undoubted Stromatopo- 

 rids), represented in figures 44 and 45 of ' The Dawn of Life,' 

 are exactly those (forming the canal-system) " of Eozoon.''^ 

 The fact, however, of their " being more regularly arranged " 

 strongly militates against this idea ; and we may add that it 

 is totally destroyed by there being no more than an analogy 

 between them. The ccmals characteristic of recent Fora- 

 rainifera are assumed by our opponents to be exactly of the 

 nature of those forming the canal-system oi^^ Eozoon. '''' " There 

 is good reason to believe," according to Dr. Carpenter, " that 

 these canals are occupied in the living state by prolongations 

 of the sarcode-body which pass from the chambers into the 

 portions of the system in nearest relation to them, and proceed 

 to its peripheral expansions "f. On the contrary, the canals 

 of the Stromatoporids referred to, and of the type species Stro- 

 matopora concentrica^ served the purpose of xoater-passages^ as 

 in sponges. They are consequently functionally different from 

 the " canal-system " of Eozoon^ and ought to be rejected as 

 direct evidences bearing on the latter structure. 



7. '"'' Canals filled loith dolomite^ 



In addition to the alleged cases of this kind that have been 

 made known, other two have appeared in ' The Dawn of Life,' 

 but described as imperfectly as the former. Therefore, if any 

 doubts attach to the new cases. Dr. Dawson must consider 

 himself to blame for them. 



We have never disputed that " canals filled with dolomite " 

 or calcite may exist ; for our investigations with reference to the 

 chemical changes in minerals and rocks have revealed sufficient 

 evidences to induce us to believe in their probable occurrence. 

 The " canal-system " in its typical form we maintain has 

 originated through the external erosion or decretion of portions 



* One of us is prepariug for publication a paper " On the Systematic 

 Position of the Stromatoporidtt.'" 



t 'Introduction to the Study of the Foramiuifera,' p. 51. 



