CORALS AND BRYOZOA. 
201 
frequent, in others very infrequent. Intercellular tissue vesiculose, the 
vesicles near the base are irregularly disposed, they are regularly super¬ 
imposed above, giving the appearance of walled septate tubuli, septa very 
numerous, almost in contact, fifteen in the space of 1 mm. Cell apertures 
oval, sometimes sub-quadrangular, length about .22 mm., width a little more 
than one-half the length, regularly and irregularly disposed, comparatively 
distant. Peristomes moderately thick, decidedly elevated, posterior jmrtion 
a little the more prominent, smooth. When the frond is well preserved the 
inter-apertural space is granulose. Surface marked by prominent monticules, 
the centers of which are distant about 8 mm., and have a granulose area 
1 50 mm. in diameter, destitute of cell apertures; the adjacent cell apertures 
radiate from these in straight lines, forming elevated rows and are larger 
than the others, gradually becoming smaller as they recede; they are more 
oblique than the ordinary apertures, and the upper portion of the cell wall is 
carinated and exposed for about .25 min._ 
The radiation of the apertures on the monticules is similar to that of Fistuli- 
pora longimacula , but the difference in the form of the monticules and the pres¬ 
ence of mesopores will be sufficient to distinguish that species. It most nearly 
resembles Lichenalia cultcllata , but may be distinguished by the non-celluliferous 
central area of the monticules, the absence of the prominent ridges, radiating 
from the centers to the adjacent apertures, and the less distinctly trilobate form 
of the apertures; internally the vesicles are more numerous and have the 
appearance of walled, septate tubuli, which is never the case in that species: 
from L. cornuta it is distinguished by the more decidedly oval cell apertures, 
absence of prominent denticulations, and much more prominent monticules and 
peristomes: from L. denticulata, of the Upper Helderberg group, by its larger 
cell apertures, much more conspicuous monticules and the absence of prominent 
denticulations: from other forms having prominent monticules it may be dis¬ 
tinguished by the small, frequently sub-quadrangular, oblique cell apertures 
and their radiation in straight lines from the centers of the monticules. 
Formation and locality. In the shales of the Hamilton group, at York, 
Livingston county, N. Y. 
