STAURASTRUM. 149 



Wood describes Si. munition, as a new species, but evidently 

 it is the same as St. arctiscon. He had it from New Hamp- 

 shire; I found it frequently in Massachusetts, Pennsylvania, 



New Jersey. No doubt it will turn up in all parts of the 

 United States. Ehrenberg had his specimens from New York. 



St. Eloiseanum, Wolle. Plate XLI. figs. 17. 18. 



Small, equal in length and breadth, smooth or finely punc- 

 tate; sinus an acute angle ; semicells subhexagonal, basil and 

 superior angles produced into short, bifurcate processes ; some- 

 times two, but oftener only discernable at each angle ; end 



view circular, margin furnished with (usually) nine,short pro- 

 cesses, ends notched. 

 Diameter 22-30 //. 



This form has some resemblance to St. spinomm, Breb , but 

 in front view, the pn>ee->es arc less conspicuous, the apices 

 less distended; in end view, circular, not triangular. 



St. duplex, Wolle. Plate LIU, figs. 6, 7. 



Small, Bubquadrangular, constriction deep, sinus acute- 

 angled; semicell, twice as broad as long, rectangular; angles 

 truncate and furnished with two, short, stout processes with 

 end- truncate granulate-spinous; end view triangular, -ides 

 straight or concave, angles truncate, divided and drawn out 

 into two short, somewhat diverging processes, apices finely 



toothed. 



Diameter '2(1-2.") n. 



Numerous in small pools, on the banks of river, Bethlehem, 

 Pennsylvania. 



The end view has a resemblance to Xordstedt's St. gemeUi- 

 parum, but front view is quite distinct. 



St. distentdm, Wolle. Plate XLI, figs. 15, 16. 



Small, smooth; semicell obovate, end convex crenulate, 

 sides in upper portion laterally produced into nearly straight 

 elongated arms, margins smooth; apices, divided into three 

 parts and distended ; end view five or six radiate ; rays taper 

 from a broad base to a distended trifid end. Between each 

 two of the bases is a deep linear sinus. 



Diameter 40 a. more or less. 



Ponds, Denmark, Splitrock, Passaic County, N. J. 



