CARBONIFEEOUS SPECIES. 55 



or nearly so, rather deep, with steeply-sloping sides, and a somewhat irreg- 

 ularly-flattened bottom, showing some appearances, as seen in sections, of a 

 low mesial prominence and other inequalities; septa very thin, about 150 

 in a specimen measuring one inch and a half" in diameter, generally nearly 

 straight, every alternate one terminating about half-way in, while most the 

 others continue to the middle, where they are sometimes slightly bent. 

 Outer vesicular zone occupying from one-third to one-half the space 

 between the wall and the middle below the bottom of the calice, occupied 

 by numerous vesicles, which, as seen in vertical sections, are generally very 

 narrow, and more or less elongated, with their longer axes ranging obliquely 

 upward and outward. Inner area occupied by nimierous, somewhat larger, 

 vesicles, which, as seen in vertical sections, have a general transverse 

 arrangement, but arch upward all around a little within the lateral mar- 

 gins of the area, and then bend downward, and again upward as they 

 approach the middle. Septal fossula, as seen in transverse sections below 

 the bottom of the calice, narrow, and extending about one-half to three- 

 fourths of the way inward from the side of the greater curve, as seen in 

 fig. 3 &. 



Length of the largest specimen seen, about 4 inches ; greatest diame- 

 ter of the calice, 1.80 inches; number of septa in one-tenth of an inch, at 

 their outer ends, about 3 to 3^. 



It is only provisionally that I have referred this coral to the species 

 described by Professor Hall. It certainly presents no characters inconsist- 

 ent with his description, as far as that goes,* and agrees with his figure, 

 excepting in having, in a larger specimen, nearly double the number of 

 septa. This latter character, however, would separate it specifically, if the 

 figure of Z. Stanshurii is correct in that particular. It is certainly very dis- 

 tinct from the species referred, by Professor Marcou, to Z. Stanshurii, in 

 his North American Geology; the specimen there represented having only 

 about sixty thick septa, not alternately shorter and longer. It will also be 

 observed that Professor Marcou's figure likewise differs in this respect 



* "Turbinate, free, or attached only by a pedicel, nearly straight, or but slightly 

 curved; cup rather deep ; margin (when entire) thin; lamellae numerous, thin; inter- 

 mediate ones extending from the margin one-third to one-half the semi-diameter; 

 fossett distinct." — (Hall, Stansbury's Eeport.) 



