192 ANNALS NEW YORK ACADEMY OF SCIENCES 



them. Where the walls are especially thick, and possibly where thin, there 

 are additional small spines or granules in single rows. Therefore tangential 

 sections vary considerably in appearance. In some, mesopores are rare, in 

 others, abundant ; in some again, only the large acanthopores at the cell angles 

 can be made out, while in others, there are smaller spines in addition in vary- 

 ing numbers. 



It may be that two distinct types have been confused under tMs title, 

 but, from the study of weathered specimens, such is thought not to be 

 the case. As a rule, however, only the larger spines are seen on weathered 

 surfaces. Owing to the thinness of the mature portion, the irregularity 

 of growth and the character of fossilization, it has been found extremely 

 difficult to secure satisfactory tangential sections, even such as are cor- 

 rectly oriented being more or less altered and obscured as to structure. 

 The thickening of the walls is not as a rule periodic, but is restricted to 

 the superficial portion. Eare instances of thickening can elsewhere be 

 noticed. The remainder of the walls is probably very thin, but its char- 

 acter is largely obscured in all material by alteration or by secondary 

 deposits. There is occasional evidence, however, of appreciable deposits 

 which are intrinsic, although not at all moniliform. Diaphragms are de- 

 veloped at rare intervals, more commonh^ near the surface. In so far as 

 my observations extend, they do not show the characteristic perforations 

 of Stenopora. 



Batostomella? armata sp. nov. 



Zoarium ramose, slender, about 4 mm. in diameter, bifurcating or laterally 

 branched. Zorpcia longitudinal in the central part, gradually sloping outward, 

 then more abruptly until, for a short distance, a radial direction is assumed. 

 Zonecia rounded owing to the thick walls, (5 or 7 in 2 mm. Walls much thick- 

 ened for a short distance near the surface, either stronglv moniliform or fused 

 into a continuous mass. Mesopores (young cells ?) rather abundant. Acan- 

 thopores numerous and very large, occurring in most of the angles. 



In tangential section, the walls appear to be greatly thickened in some areas 

 and much thinner in others. The zooecia are completely rounded or sub- 

 angular, according to the degree of development of this feature. The large 

 acanthojiores are imbedded in the thick wnlls but indent the cells where the 

 walls are thinner. Where the walls are thick, a row of large granules occu- 

 pies the median line ; wh^re thin, the granules are wanting, but a strong, con- 

 tinuous line appears. Diaphragms are developed to a limited extent and 

 chiefly in the cortical zone. Their distribution is rather scattering and far 

 apart, slightly more than one diameter on an average, but varying from about 

 two thirds to nearlv 2. ]\Iacul;p probably present and indicated in thin sec- 

 tions by groups of not conspicuously larger cells, possibly also by the varying 

 thickness of the walls. 



