J. G. WALLER ON PARASITIC VEGETABLE ORGANISMS. 347 



vails as in those countless ages past, and I shall further show you 

 that these organisms, living and fructifying many fathoms deep off 

 our coast, may be illustrated by what are found in our woods, not 

 much beyond the Metropolitan area, as well as in the Silurian 

 corals. 



The grains of calcareous sand in which they are found vary in 

 size from the twentieth to half the inch, and there are proofs, that it 

 is whilst in this comminuted state the plants grow and flourish, as 

 some directly conform to the rounded shapes of the particles. They 

 are in all conditions. Some beginning their development from mere 

 granules ; some fully developed ; some exhibiting their reproduc- 

 tive powers ; and of others we see but their excavations. Though 

 it must be obvious, that there is much difficulty in following oat 

 the life-history of organisms growing under such special condi- 

 tions, I have been careful to note every fact which examination by 

 the microscope has given to me ; and I have derived much aid from 

 the admirable handbook of the " British Fungi " of our President 

 (Dr. M. C. Cooke). I believe I shall be found to be correct, when I 

 refer these plants to the Fungi, but it is well to state, that there have 

 been conflicts of opinion respecting organisms closely allied, some 

 placing them, or at least some species, amongst the Conferva?, or 

 with the Alga3. But there seems now to be a pretty general con- 

 sent that they belong to a group of the Fungi. Kolliker says — 

 " It seems to me probable that the parasites dissolve the carbonate 

 of lime of the hard structures, into which they penetrate by means 

 of exudation of carbonic acid, which secretion would seem to take 

 place only at the growing ends of the fungial tubes."* 



Without attempting to class the organisms, which I shall now 

 place before you, amongst forms developing under other conditions, 

 I must, however, draw your attention to the analogies which they 

 exhibit, although that may only be superficial. We must keep in 

 mind that we are dealing with excavations, and that none of the 

 forms develope externally. There are two groups of Fungi, viz., 

 the Perisporacei and the Sphaeriacei, to which I must refer. The 

 first is defined as having minute globular perithecia, bursting at the 

 summit, being filled with a gelatinous substance " Sporidia pro- 

 duced in asci, subsequently often effused, simple, free, and mixed 

 with the gelatine." That of the Spha3riacei is stated to have " the 



* " Proceedings of Royal Society," June 9, 1859, Vol. x. 



