CORALS AND BRYOZOA. 
7 
marked by very strong longitudinal striae, increasing in number with the 
size of the cell tube and giving to the margins of the walls a crenulated 
appearance. Mural pores large, circular, invariably occurring on the longi¬ 
tudinal ridges. 
This is the most robust species of the genus yet noticed, and the cells are 
large in proportion ; it is not a common form and is generally found in detached 
pieces on the weathered surfaces of blocks of limestone. 
Formation and locality. In limestones of the Lower Helderberg group, Clarks¬ 
ville, N. Y. 
MI CHE LIN I A, De Ivoninck. 1842. 
Michelinia lenticularis. 
PLATE III, FIGS. 1,2, 3,5. 
Michelinia lenticularis, Hall. Twenty-sixth Rept. N. Y. State Mus. Nat. Hist., p. 113. 1874. 
“ “ “ Thirty-second Rept. N. Y. State Mus Nat. Hist., p. 145. 1S79. 
“ “ “ Report of State Geologist for 1882. Expl. pi. 3, figs 1, 2, 3, 5. 18S3. 
Corallum forming small lenticular bodies, the lower surface usually the less 
convex and covered with a strongly wrinkled epitheca. Cells large and few, 
usually from seven to twelve; broadly campanulate. Partition walls about 
1 mm. thick ; strongly marked longitudinally by nodose striations; den¬ 
ticulate on the margins. The number of striations and denticulations varies 
with the size of the cell. 
In a characteristic specimen 20 mm. in diameter, there are eight cells, the 
central one having a diameter of 11 mm., and the peripheral cells measuring 
from 6 to 8 mm. across. The entire height of this specimen is 9 mm. 
This is a very small species, seldom attaining a diameter, of more than 25 
mm., and is distinguished by its large cells and their strongly granulose-striate 
character. A small individual 10 mm. in diameter shows one large central 
cell and six smaller ones around the margin, also an incipient seventh cell. 
Occasionally there are two central cells in large individuals, and the number of 
peripheral cells in such specimens is from ten to twelve. 
Formation and localities. In the shaly limestone of the Lower Helderberg 
group, near Clarksville and Schoharie, N. Y. 
