Dr. H. A. Nicholson on the Genus Climacograpsus. 375 
canal" for the conveyance of the coenosarc. This is also 
the structure in all the Diplograpst which I have had an 
opportunity of examining in a sufficiently good state of pre- 
servation. 
From the peculiar nature of the cellules in C. teretiusculus, 
and in all other members of the genus Climacograpsus, it will 
be at once seen that all the views of the frond which can 
term as applied to a monoprionidian species. In well-pre- 
served specimens exhibiting this view, two faint lines proceed 
outwards and downwards, one from each angle of the trans- 
verse aperture, marking the position of the cell-partitions. 
the row of cellules on the opposite side of the frond to be seen 
indistinetly through the test. Between these extreme terms 
