Up2)er Helderlerg Group. 



161 



THAMNISCUS, King, 

 Thamxiscus nanus, n. sp. 



"Width of branches varying according to distance from the base; 

 non-celluliferous side rounded, just below the bifurcations somewhat 

 fattened, on the specimens observed the branches are smooth ; cells 

 tubular, cylindrical, arising just within the non-celluliferous surface 

 of the branch; for a portion of their length they are essentially paral- 

 lel with the surface, then turning abruptly, and frequently opening 

 directly outward ; cell-apertures circular or slightly oval, diameter .25 

 mm., irregularly disposed, sometimes forming transverse rows, the ele- 

 vated margins of the apertures, forming the rows, are in contact, mar- 

 gins of apertures strong ; frequent maculae .50 mm. in diameter, des- 

 titute of apertures. 



Locality — Falls of the Ohio river. 



Thamxiscus multiramus, n. sp. 

 Bifurcations occurring at intervals of from two to five mm. ; many 

 of the branches cease growth after one or two bifurcations; v/idth of 

 branches from .5 to 1.50 mm., sometimes equally bifurcating, at other 

 times one branch is much the smaller ; non-celluliferous side gently 

 rounded or flattened, finely striated; cell-apertures circular, diame- 

 ter .15 mm. 



Locality — Schoharie, N. Y. 



CYSXaPORA, nov. gen. 



Bryozoum consisting of simple or branching sub-cylindrical stipes, 

 cells arising from the axis, circular and sub-cyHndrical bplow% enlarg- 

 ing above the middle of their length, and becoming ampullate, turn- 

 ing abruptly outward below the apertures, which are extremely con- 

 tracted; cell tubes exposed for more than half their length. 



Cystopoka gexiculata, n. sp. 



Length of tubular cells two mm., for the space of one mm. nearly 

 parallel with the axis of the branch, the walls of one-half of the tube 

 being exposed ; at a short distance from the aperture the tube is con- 

 stricted, abruptly turning and continuing at right angles to the 

 former portion ; diameter of widest portion of tube .50 mm., of the 

 narrowest .18 mm.; diameter of branch one mm.; cells alternating, 

 imbricating and forming spiral rows. 



Locality — Falls of the Ohio river. ^ 

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