562 Report of the State Geologist. 



two prominent denticulations, producing a crescentic projection ; 

 intercellular space vesiculose; surface with elongate depressed 

 maculae, destitute of cell apertures. 



Pileotrypa, Hall. 



(Pal. N. Y., Vol. YI, p. xvi. 1887.) 



Type, Pileotrypa denticulata, Hall. 



(Plate23, figs. 8-15.) 



Zoarium usually consisting of thin in crusting expansions, but 

 one form having the same characters is ramose, branches hollow. 



Cell tubes very oblique, ^frequently imbricating, pseudoseptate ; 

 cell apertures trilobate, irregularly disposed, or alternating and 

 imbricating ; anterior portion of the peristome slightly elevated ; 

 posterior portion strongly elevated, projecting over and partially 

 concealing the aperture ; denticulate ; on some parts of the frond 

 the upper portion of the cell tubes are frequently exposed for a 

 third or more of their entire length ; intercellular space occu- 

 pied by irregularly disposed vesicles on tabulate mesopores ; 

 surface with frequent monticules the centers of which are desti- 

 tute of apertures ; from this space the cell apertures radiate in 

 every direction ; interapertural space solid. 



G-I0S80TRYPA, Hall. 



(Pal. N. Y., Yol. Yl, p. xvii. 1887.) 



Type, Glossotrypa paliformis, Hall. 



(Plate 24, figs. 8-10.) 



Zoarium tubular, cylindrical, hollow; diameter of tube 2 mm.; 

 thickness of zoarium .40 mm. Cells tubular, with frequent 

 narrow projections, (semi diaphragms) from the cell walls, extend- 

 ing partially across the tube; two pseudosepta on one side; cell 

 apertures paliform, very closely disposed, frequently in diagonally 

 intersecting rows; the surface presenting a reticulated appear- 

 ance; apertures with denticulated lunarium; interapertural space 

 elevated, forming ridges; frequently a prominent node at the 

 intersection of the ridges ; sometimes a depression or pit ; surface 

 with monticules which are laterally in contact, giving to the frond 

 an annulated appearance ; intercellular space vesiculose. 



