CORALS AND BRYOZOA. 201 



frequent, in others very infrequent. Intercellular tissue vesiculose, the 

 vesicles near the base are irregularly disposed, they are regularly super- 

 imposed above, giving the appearance of walled septate tubuli, septa very 

 numerous, almost in contact, fifteen in the space of 1 mm. Cell apertures 

 oval, sometimes sub-quadrangular, length about .22 mm., width a little more 

 than one-half the length, regularly and irregularly disposed, comparatively 

 distant. Peristomes moderately thick, decidedly elevated, posterior portion 

 a little the more prominent, smooth. When the frond is well preserved the 

 inter-apertural space is granulose. Surface marked by prominent monticules, 

 the centers of which are distant about 8 mm., and have a granulose area 

 1 50 mm. in diameter, destitute of cell apertures ; the adjacent cell apertures 

 radiate from these in straight lines, forming elevated rows and are larger 

 than the others, gradually becoming smaller as they recede ; they are more 

 oblique than the ordinary apertures, and the upper portion of the cell wall is 

 carinated and exposed for about .25 mm. 



The radiation of the apertures on the monticules is similar to that of Fistuli- 

 pora longimacula, but the difference in the form of the monticules and the pres- 

 ence of me.sopores will be sufficient to distinguish that species. It most nearly 

 resembles Lichmalia cullellata, but may be distinguished by the non-celluliferous 

 central area of the monticules, the absence of the prominent ridges, radiating 

 from the centers to the adjiicent apertures, and the less distinctly trilobate form 

 of the apertures ; internally the vesicles are more numerous and have the 

 appearance of walled, septate tubuli, which is never the case in that species : 

 from L. comuta it is distinguished by the more decidedly oval cell apertures, 

 absence of prominent denticulations, and much more prominent monticules and 

 peristomes : from L. denticulata, of the Upper Helderberg group, by its larger 

 cell apertures, much more conspicuous monticules and the absence of prominent 

 denticulations : from other forms having prominent monticules it may be dis- 

 tinguished by the small, frequently sub-quadrangular, oblique cell apertures 

 and their radiation in straight lines from the centers of the monticules. 



Formation and locality. In the shales of the Hamilton group, at York, 

 Livingston county, N. Y. 



