48 
strong, definite, numerous acanthopores, as shown by the 
section taken farther below the surface. This section also shows 
the zooecia as varying from round to polygonal and only slightly 
separated from one another by a few angular mesopores. 
In a vertical section the walls are seen to be slightly crenu- 
lated, never definite, and exhibit a diffuse granular structure. 
The young tubes arise in the axial region and expand rapidly as 
in Nicholsonella pulchra. The diaphragms are few and far 
between in the axial region, but in the peripheral region are more 
numerous, averaging from once to twice their own length apart. 
The species is readily distinguished from others of this 
genus by the size of its zooecia, the strong numerous acantho- 
pores, and the fewness of the mesopores and diaphragms. 
Formation and Locality. Leray beds of the Black River, 3 
miles east of Ottawa and Rockland beds at Rockland. 
Escharopora frondosa n. sp. 
Plate II, figures 5, 6 
A bifoliate frond having fairly numerous monticules with 
only slightly enlarged zooecia. The apertures have the typical 
intersecting Escharopora arrangement and are surrounded by 
sloping hexagonal areas. The longitudinal axis is the greater. 
In 2 mm. there are from eight to nine zooecia taken across the 
frond, seven taken on the diagonal, and four taken vertically. 
This difference in number is due in the main to the arrangement 
of the zooecia, not to the difference in the length and breadth of 
the apertures. It will be seen that the intersection of rows 
means that there will be at least three apertures of an adjacent 
row dove-tailed into any four that are taken in a true vertical 
measurement. 
Internal Characteristics. A vertical section is almost iden- 
tical with E. confluens except that the frond is thinner. A tan- 
gential section, however, shows that the zooecia of E. frondosa 
are not as elongated as those of E. confluens , although they do 
exhibit some tendency towards the “confluent’' form of the 
latter. The species, however, is readily distinguished by the 
form of growth of the colony. 
