176 KOLLIKER, ON VEGETABLE PARASITES. 



hornv fibres, but on their exterior, in a few instances, opaque 

 rounded bodies were seated, which were probably sporangia, 

 but this I was unable definitively to determine. It was 

 remarkable also that in many places the fungus-filaments 

 presented large, sinuous, elongated dilatations which occupied 

 nearly the whole thickness of the fibre. 



2. POLYTHALAMIA. 



The close examination of a considerable number of sections 

 of Polythalamia, for which I have been indebted to the kindness 

 of my friend Dr. Carpenter, afforded the definite result that 

 in these delicate organisms also a parasitic vegetation is not 

 wanting. Owing, moreover, to the circumstance that in 

 certain of these creatures the shells, also typically contain 

 special systems of tubuli, it is often extremely difficult to 

 decide as to the true nature of the tubuli. The genera in 

 which vegetable parasites, which I also look upon as fungi, 

 have been noticed, are the following : 



1. Operculina. (Fig. 7.) 



In the shells of this genus Dr. Carpenter has described two 

 kinds of tubes, the one fine and closely placed, which run 

 vertically and unbranched, in the upper and lower walls of 

 the chambers, and the other usually constituted of somewhat 

 larger anastomosing canals, which are found in the marginal 

 layer of the shell, whence they penetrate into the vertical 

 dissepiments of the chambers. That the former represent a 

 normal structure does not admit of the least doubt, but with 

 respect to the others any decision is rendered very difficult 

 owing to the circumstance that, together with them, very 

 numerous parasitic structures certainly occur. One circum- 

 stance, however, may be noticed which throws light upon the 

 matter; the fact, namely, that in certain individuals the 

 parasites are entirely absent, and that there are genera 

 possessing essentially similar structural conditions, which also 

 exhibit nothing of the sort. Of six preparations of Operculina, 

 parasites appear to be entirely absent in five, whilst in the sixth 

 they occur in enormous quantity. Two preparations of the allied 

 Cycloclypeus Australis present no structures whatever of the 

 parasitic kind, and the same was the case in four sections of 

 Nonionina Germanica. It was thus definitively proved that the 

 second system of tubuli noticed by Carpenter in the species 

 is, as it is described and figured by that naturalist, typical. 



Now with respect to the parasitic fungi which were met 

 with in the one specimen of Operculina, they were found, in 



