Prof. Schwergger's on the Corallina opuntia. 221 



served in museums. On dividing the green stalks, a number of 

 filaments and a bright green parenchymatous substance could 

 be distinguished with the naked eye. Under the microscope, 

 the filaments appeared as succulent fibres or soft narrow bands 

 interwoven and branched irregularly. In the recent state, the 

 filaments had a great resemblance to the soft fibres of the Alci/- 

 onium bursa, Linn, (now considered a plant) ; as they became 

 dry however, particularly in the older branches which had har- 

 dened by their copious deposit of calcareous matter, the fila- 

 ments appeared jointed, and this was especially observed in the 

 latter, on removing the lime by means of nitric acid. In this 

 state their resemblance to the filaments of confervae and the ves- 

 sels of fuel was obvious. The vegetable nature of the Cor. 

 opnniia, appeared still more distinct in its general structure. 

 The outer covering appeared under the microscope, uniform 

 or striated longitudinally, the striae being composed of short ca- 

 nals or cells ranged above each other in irregular lines. These 

 lines are undoubtedly mere remains of the cellular texture left 

 attached to the inner surface on removing the covering. The 

 structure of the cellular substance distinctly indicates this coral- 

 line to belong to the vegetable kingdom. The parenchyma is 

 seen to be composed partly of globular, partly of pentagonal or 

 hexagonal cells, precisely as we find it in the generality of plants, 

 but never in animals. The soft filaments above described are 

 extended between these cells. The younger the branch is, the 

 more distinct is this structure, the cells in the young state be- 

 ing soft and green ; but, after the lime is deposited in the cellu- 

 lar tissue, the cells become almost undistinguishable ; by remo- 

 ving the lime with acids, however, tlicy are brought again into 

 view, more or less distinctly, according to the age of the branch. 

 In young portions we discover a number of minute granules in 

 the cellular texture between the filaments. They are not perceiv- 

 ed in older branches ; and, even when the lime is removed, they 

 are still either imperceptible, or are observed in much smaller 

 quantity than in the former. These granules are obviously not 

 calcareous, since they do not disappear when the young branch 

 is immersed in nitric acid. In their general appearance, and 

 in the circumstance of their collecting principally in the young- 

 est portions, they exhibit a striking resemblance to the granular 



