MINUTE STEUCTFEE OF STEOMATOPOEA AND ITS ALLIES. 227 



flucnces for the production of most if not all of their canalicular, 

 and what may be termed poriferous aspects. The similitude to 

 what is extant in certain of the Stromatoporoids in this connexion 

 suggests caution in the interpretation of these structures in the 

 latter. 



2. To Foraminifera. — "We may next briefly consider the chief 

 facts bearing upon the relationship of the Stromatoporoids to the 

 Foraminifera — a relationship whicli has been frequently sug- 

 gested, and w^hich has been more especially insisted on by Prin- 

 cipal Dawson (' Daw^n of Life,' p. 156 et seq.) 



As this distinguished observer, we believe, is about to publish 

 in full the results of his investigations into this subject, we shall 

 merely make a few brief remarks on the question, the more so as 

 we have already (see pp. 193 & 195) referred to Dr. Dawson's views 

 so far as published. If w^e compare such a Stromatoporoid as those 

 which we have described under the name of Clathrodictyon with 

 such a Foraminifer as Tinoporus, there is no doubt as to the 

 striking general similarity in minute structure ; but this simila- 

 rity becomes much reduced if we take for the purpose of this 

 comparison the more regular and typical forms constituting Stro- 

 matopora proper. In thin sections of Clathrodictyon cellulosum, 

 Nich. & Murie, we have thought that we have been able to make 

 out minute microscopic tubuli, placed side by side, and uniting 

 neighbouring compartments of the fossil directly with one another. 

 If we could have established this point (and we have seen similar 

 appearances in some other forms), then we might have instituted 

 a direct and close comparison between Clatlirodictyon and Tino- 

 porus. Unfortunately, we have not been able to satisfy ourselves 

 thoroughly that these apparent tubuli have any actual existence 

 even in the forms above alluded to ; whilst in the great majority 

 of forms vfQ have failed to detect any traces of similar structures- 

 So far as our present observations go, therefore, we are unable to 

 assert positively that the skeleton of the Stromatoporoids is per- 

 forated by any system of microscopic tubuli, similar to the tubuli 

 found in the test of the Perforate Foraminifera ; and we do not, 

 therefore, feel ourselves justified in considering that there is any 

 direct affinity subsisting between the two groups of organisms. 



Exception, however, may be made to Loftusia and ParJceria. 

 Amongst the undoubted fossil Foraminifera, the nearest ally of 

 the Stromatoporoids is probably to be found in the gigantic arena- 

 ceous Foraminifcrs of the Greensand described by Dr. Carpenter 



