198 PALEONTOLOGY OF NEW YORK. 



This species may be distinguished by the sub-trilobate form of the apertures, 

 their distance from each other, the nearly equally elevated peristomes and the 

 smooth, Hat, inter-apertural space. 



Formation and locality. Hamilton group. Western New York ; particular 

 locality not recorded. 



Lichen ALIA vesiculata, n sp. 



PLATE LVn, FIGS. 14-19; AND PLATE HX, FIGS. 1, U. 



ZoARiUM consisting of lamellate expansions free or incrusting other objects, 

 generally Cyathophylloid corals ; no massive specimens have been observed ; 

 thickness of fronds from 1 to 3 mm. ; under surface a thin epitheca with 

 strong, concentric wrinkles, and obscure, rounded, radiating markings, caused 

 by the recumbent portion of the cell tubes. Cells tubular, cylindrical, for 

 nearly their entire length at right angles to the surface, septate ; septa very 

 thin, moderately frequent ; cell walls finely wrinkled or corrugated. Inter- 

 cellular tissue vesiculose, vesicles comparatively very large and irregularly 

 disposed near the base, more regularly superimposed above, but in the 

 specimens observed, never having the appearance of walled septate tubuli ; 

 width of a vesicle generally about equal to that of a cell aperture, fifteen or 

 twenty in the space of 5 mm., measured longitudinally. Cell apertures nearly 

 circular, having a small fold or plication in the posterior portion of the walls, 

 which frequently gives an obscurely trilobate or triangular form, diameter 

 .50 mm., closely disposed, often in contact, frequently forming irregular, 

 intersecting rows. Peristomes strong, equally elevated, not denticulated, 

 when well preserved the summits are obscurely granulose, giving them 

 a minutely, serrulate appearance. Inter-apertural space flat, when well 

 preserved granulose, when slightly macerated smooth. Surface marked 

 by elongate-depressed maculae, having a length of 5 mm., width about 1 

 mm., and destitute of cell apertures. The cell apertures immediately adjacent, 

 are not larger than the others and sometimes the general direction is not 

 altered. On some fronds the cell apertures are distinctly trilobate (Plate 59, 

 fig. 1), but these fronds, in all other respects, agree with the ordinary forms 

 of the species. 



