KOLLIKER, ON VEGETABLE PARASITES. 177 



the first place, in the dissepiments, accompanying and running 

 among the larger tubuli of Carpenter, but secondly, also 

 among the finer tubuli in the thick walls of the chambers. 

 They everywhere presented the aspect of more or less 

 sinuous, irregular, branching, and also frequently anastomosing 

 tubes. But whilst in the former situation the canals were 

 rather wide, so as to measure even O002'" to 0003'" and more 

 in diameter; in the latter, fine tubuli of the same diameter as 

 those of the shell were the more numerous. The adventitious 

 tubuli, however, were readily distinguishable from the others 

 by the circumstance that they were spread out in a horizontal 

 network, and consequently ran at right angles with the proper 

 tubuli of the shell. Of sporangia I noticed only in one spot 

 some indications on a rather wide canal, upon which were 

 visible two rounded, opaque swellings ; but I would not venture 

 to assert that these bodies were really sporangia. 



2. Amphistegtna. (Fig. 5.) 



Five sections of this genus contained fungi. They oc- 

 curred principally in the marginal parts of the shells, and 

 appeared as branched canals, about , 002'" or - 003'" in dia- 

 meter. Besides these wider canals, others of less dimensions 

 also occurred, which I think must be regarded as of the 

 same nature, especially on account of their horizontal and 

 often much lengthened course. No sporangia were observed 

 in this case, whilst in certain spots in those parts of the shell 

 which bounded the chambers very young individual fungi 

 might be observed, under the form of short pyriform vesicles, 

 whose narrow extremity was directed towards the cavity of 

 the chamber. 



3. Heterostegina 



Contains fine-branched and, as it would appear, occa- 

 sionally anastomosing fungus-filaments, running chiefly in 

 a horizontal direction between the fine tubuli of the shell 

 which they thus crossed. No sporangia. 



4. Calcarina. 



Three sections of this genus contained a few fungi, repre- 

 sented by sometimes fine and branched filaments, some- 

 times by wider, short, pyriform, and elongated tubules, 

 aggregated in the most superficial layers of the shell, and 

 which probably represented a younger condition of the 

 other filaments. No indication of sporangia. 



