i882.J The Paleontologist. 5^ 



the upper surface very gentle at first, in most cases forming quite a flat 

 expansion all round, becoming more abrupt further inward and upward, and 

 conical or dome shape above at angles (in cases of the cone shaped forms) 

 of from 35 to 75 or 80 degrees; broken away in most cases, at heights 

 varying — different examples — from one half an inch to over one inch 

 above the center of the base, showing, with rare exceptions, the continued 

 growth of the corallum, to what extent not apparent, but, from the various 

 shaped fragments found with similar, general, surface markings and internal 

 structure, the evidence is that it did not grow very high or much expanded, 

 but threw out blunt projections in different directions. Distributed over 

 the snrjace are maculae of groups of calices, larger than the average, 

 occupied in the center, in many cases, but not always, by a few small 

 pores ; the maculas from being even with the general surface are often 

 raised, gradually, from one specimen to another, to decided, conspicuous 

 •• 7.'zc«//r///^5'," irregularly arranged from one to two lines apart. Mar- 

 gins of cell apertures, of unworn specimens, thin and sharp, Calices 

 polygonal, 7 or 8 in the space of one line, except the larger ones in the 

 groups, which are, in some cases, nearly double that size ; very few 

 small interstitial tubes noticed. 



A vertical SQQ.'ixon of the inteiior, taken from the basal part of a speci- 

 men where it has attained the thickness of ^ of an inch, shows the cor- 

 allites to be direct from the base to the outer, upper surface ; the walls 

 thin and slightly curved; the tabulge, which are as thick as the tube walls 

 in this section, are numerous, complete and generally horizontal across 

 the tubes, but occasionally they pass in an oblique direction, and at 

 different widths apart, sometimes having the appearance of bands. 

 There is no difference of tabulation between the larger and smaller 

 tubes, one no more numerous than the other. A section taken from the 

 upper part of the specimen, at the height of one inch from the center of 

 the base, shows the walls of corallites and tabulation identically the same 

 as above described. In tangential section the corallites are thin-walled, 

 polygonal in shape, varying in size as on the outer surface; no " spini- 

 form" tubes observed. A transverse section, near the base, shows the 

 tubes very much the same as the tangential, with the exception of the 

 walls not being quite so sharply defined. In a longitudinal section taken 

 from a specimen of an upper projection, appearing to have a tendency to 

 branch, the tubes, in the central region, have, at first, a confused ap- 

 pearance, but change as they curve abruptly and pass directly to the 

 surface; in this section the tube- walls become thickened toward the sur- 

 face, but the tabulae are the same as in the lower sections, unless, per- 

 haps slightly more numerous. A transverse section of the same speci- 

 men, where the shape is subcylindrical, shows the walls of corallites to 

 be thin in the axial region, but thickened outwardly with no apparent 

 difference in tabulation. In a section taken from another sub- cylindrical 

 specimen, the only difference appreciable is the slightly more remote 

 tabulffi of the central region. 



Some specimens of this species resemble, quite closely, some examples 

 of sp. patasiforinis, Nicholson, and it may prove to be only a variet}'. 



