138 



Notes on a Group of Marine Microscopic Vegetable 

 OrganiSxMS invading Calcareous Organic Remains. 



By W. H. Harris. 



{Read Noveonder ISth, 1S98.) 

 Plates 9 and 10. 



Introduction. 



For many years past I have devoted considerable attention to 

 the study of the Foraminifera, and dredgings from many parts 

 of the world have come under my observation. Very early in the 

 course of my investigations I observed that these organisms, 

 together with fragments of molluscan shells, sponge spicules, and 

 countless other kinds of organised material presented various 

 conditions of preservation. The brilliancy of a recent test, or 

 lately cast-off shell, immediately attracted my attention, and in 

 contrast to this, those which had been discarded for some length 

 of time ; the latter appeared dull, the surfaces were very obviously 

 defaced and sometimes discoloured, channels and variously-sha{)ed 

 ca\'ities were present, their substance was invaded by something 

 prejudicial to their preservation, and disintegration had com- 

 menced. Thus, early in my studies, I was led to inquire into the 

 nature of the agency which caused this breakmg-up. It was 

 clear that simple chemical action was not the cause ; there was a 

 tolerable uniformity in the size and form of the excavations, and 

 in some instances they were connected with each other by channels 

 of extreme minuteness, and of almost uniform diameter ; such 

 appearances would scarcely result from inorganic chemical action. 

 There remained, then, the alternative — the appearances were 

 the result of organic action. Naturally I became anxious to 

 know as much as possible about the little organisms whose 

 destructive work T could so plainly see, but the way in which 

 it was performed I was even unable to conceive. 



About this time I was corresponding with one of your members, 



