STUDY OF THE GENICüLA OF CORALLINE. 21 



blue very deep. When stained with the former it can not be 

 distinguished 1V.hu the second lamella : very thin: taking the innermost 

 position of cellwall. Often this lamella can hardly be detected. 



The extragenicular portion has several different characters in 

 comparison with the genicular portion proper. The wall of the former 

 part is not as thick as that of the latter, and there is always, after 

 preparation, a longitudinal space left between each cell. When 

 stained by an ordinary colouring reagent, this space remains unstained, 

 apparently suggesting the intercellullar space. When, however, the 

 sections were treated in ruthenium red by the proper method, this 

 space assumed an intense red colour. It is beyond doubt that the 

 space is filled with a. substance which has a peculiar character. 



The cellwall of the extragenicular portion consists essentially of 

 the continuation of the primary cellwall of the genicular portion 

 proper. Its colouring reactions are always the same. And at the 

 same time we do not doubt that this primary cellwall is that from 

 which is constructed the whole framework of the articular cells. At 

 the inner part of the wall we have a thin layer, which it is difficult 

 to detect in some case, and which continues to the secondary lamella 

 of the genicular cells. The thickness of the secondarv lamella 

 increases abruptly at the critical points between both the extragenicular 

 and the genicular portions. 



The extragenicular portions of the genicular cells, as has been 

 lormerly mentioned, contain deposits of calcium carbonate, while 

 the genicular [tortious proper are destitute thereof. We often meet 

 with preparations which have the genicular portions much shrunken and 

 the extragenicular portions remaining in the original state. In those 

 preparations we find the primary cellwalls of the genicular portions 

 much fimbriated near the transitional points. This is probably due 

 to the difference in the properties of the primary cellwall and the 



