196 ANNALS NEW YORK ACADEMY OF SCIENCES 



the small ones occur in 2 mm. Mesopores rare or absent. The walls are 

 thin and the zooecia polygonal. Acanthopores moderately large, developed at 

 the angles of the cells which they often indent, rarely at the sides. Occasion- 

 ally, a section is so directed that acanthopores seem to be almost absent. In 

 longitudinal section, the prostrate portion is seen to be short and the rest of 

 the zooecium long and straight. The walls are thin, with inconspicuous thick- 

 enings which are small in degree and apt to occur at long and rather irregular 

 intervals. For this reason, the walls in cross section appear thin, the cells 

 angular and the acanthopores projecting into them. The diaphragms are thin, 

 often conspicuously perforated, abundant, occurring from one half to two 

 diameters apart. The average is one diameter or less, and the longer intervals 

 are rare, tending to occur simultaneously in several cells. 



Stenopora emaciata var. megastylus var. nov. 



Zoarium explanate, from 2 to 7 mm. thick in different parts. Lower sur- 

 face covered with a wrinkled epitheca. Distinctly monticulate with large cells 

 on the monticules. Zooecia very variable in size, 6 or 7 in 2 mm., subaugular. 

 Walls thin, with gently elongate swellings. In tangential section, thin-walled 

 areas alternate with areas made up of cells having distinctly thicker walls. 

 Acanthopores large, usually on the cell angles, truncating the angles or in- 

 denting the cells. Diaphragms closely arranged, fi'om one half to one diam- 

 eter apart, conspicuously perforated. 



Stenopora intermittens var. harrisonensis var. nov. 



Zoarium in the form of thin expansions less than 5 mm. in thickness. Super- 

 ficial characters not known. Aggregations of larger and smaller cells rathei 

 conspicuous. About 6 occur in 2 mm. In sections transverse to the tubes, 

 their walls show great variation in point of thickness, the thin ones being 

 almost linear and the thick ones in extreme cases one half the diameter of 

 "the tube. The cells which are bounded by them are in the one case angular 

 and in the other circular. The acanthopores are extremely large. Where the 

 walls are thin, they indent the cells, although part of the wall is carried 

 around on either side, tending to give the cells a more circular shape, but 

 they are completely imbedded in the walls, when the latter are thick. When 

 such is the case, there is seldom any visible median. line, but there are occa- 

 sional spines in addition to the true acanthopores. In longitudinal section 

 also, two types of thickening can be noted, some of the walls being almost 

 linear with only occasional short but not very strong swellings, while others 

 are continuously and regularly thickened. — some very heavily so. Diaphragms 

 are irregularly distributed, a diameter or less apart in some areas and much 

 more than a diameter in others. 



Stenopora miseri sp. nov. 



Zoarium consisting of thin expansions covered below by a wrinkled epitheca. 

 The individual sheets are apt to be contorted. They occur singly or super- 

 posed, or Interlaminated with Fistulipora excellens. In combination, they 

 form bodies of considerable thickness, but they are not solid, since relatively 



