4 
PALAEONTOLOGY OF NEW YORK. 
gemmation. Generally there are two buds from each cell, diverging at an 
angle of about 45°. Interior striated; exterior transversely corrugated and 
strongly striated longitudinally. Length of cell tubes about 2 mm.; diam¬ 
eter at the aperture slightly more than 1 mm. 
This species differs from A. Schohctria in its shorter tubes and proportionally 
greater diameter, its more frequent gemmation and closer aggregation of growth. 
Formation and locality. In the shaly limestone of the Lower Helderberg 
group, Schoharie, N. Y. 
Aulopora subtenuis. 
PLATE II, FIGS. 9-13 and 15- IS. 
Aulojjora subtenuis, Hall. Thirty-second Rept. N. Y. State Mus. Nat. Hist., p. 143. 1S79. 
In part “ “ “ Report of State Geologist for 1882. Expl. pi. 2, figs 9-20. 1883. 
Corallum consisting of elongate, slender, curving, tubular cells, very gradually 
enlarging to the aperture. Usually increasing by a single gemmation from 
each cell-tube, but sometimes there are two and very rarely three buds. Tubes 
usually straight to the point of gemmation, after which they turn abruptly 
to one side and cease growth as shown in tigs. 10 and 11. When there is 
more than a single gemmation the parent tube continues curving and the 
buds emanate from the convex or posterior side, as shown in fig. 16. 
Interior smooth; exterior strongly corrugated and longitudinally striated; 
many specimens finely granulose. Length about 8 mm.; diameter at the 
aperture 1 mm., at smaller end .75 mm. 
This species may be distinguished from A .Schoharicc by its more slender form, 
greater length, and by its mode of gemmation. In A. Schoharia, when two buds 
proceed from a parent tube, they are at about the same distance from the 
aperture, one on each side of a central line, while in this species they are in 
the middle of the posterior part of the tube, in a direct line and sometimes 
2 mm. apart. In all the specimens, so far observed, the cells turn to one side 
and do not turn upward after budding. 
Formation and locality. Lower Helderberg group, near Clarksville, N. Y. 
