4 PALAEONTOLOGY OF NEW YORK. 



geinraation. 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. Schoharia 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. 



Adlopora subtendis. 



PLATE H, KIGS. »-13 AND 15^ 18. 



Aulojxira subtenuis. Hall. Thirty-second Rept. N. Y. State Mus. Nut. Hist , p. 143. 1879. 

 In jMU-t " " " Report of State Geologist for 1882. Expl. pi. 2, tigs 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 figs. 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 Schoharia by its more slender form, 

 greater length, and by its mode of gemmation. In A. Schoharia, when two buds 

 proceed from a parent tube, tiiey 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. 



