270 TRANS. OF THE ACAD. OF SCIENCE. 
lique lines six dimples are found on a surface slightly waved 
transversely. Cell pores five in oblique lines, five transyerse- 
ly; cells with penbiionss round lips; apertures round or sub- 
oval, larger and more distinct on the borders of the: 
bottom of the dimples marked with cells which seem to hay 
n rythmically abortive. In one specimen, where the cells 
are worn, the labial borders are destroyed, and the cells ap- 
more or less eae or suboval. This peepee 
to those of the wider expansions the s 
which we bate described above | : 
_ Formation wena ey: Archimedes. Limestone Wee 
: mesial _—- is seen — ates a 
