- I Ml: U5TRUM. 135 



lightly rounded inferior angles, each armed with a strong, 

 short, amicus. End view quadrangular, four rayed. 



Diameter 62-75 fit.; length 15 fit. 



Splitrock pond, Passaic County, N. J. 



St. Rotula, Nord. Plate WAV. figs. 13, 14. 



Large, punctate, profoundly constricted; semicells subhex- 

 agonal, top truncate and furnished with a few teeth; angles 

 produced laterally into long, straighl rays, margins with three 

 (or four?) tooth-like prominences; end view circular with 

 seven to nine straight rays, margins tri-dentate-crenate, apices 

 tritid ; at the base of each ray a large granule, ana between, 



punctate. 



Diameter 881 25 ". 



Denmark', Splitrock, and other ponds, Passaic County, N.J. 

 Very rare in Pennsylvania. 



St. oronuiiAtum, Wolle. Plato X Id V, figs. 11. 12. 



Twice a- wide as long ; -en i ic 1 1 - obovate ; sides produced 

 into somewhat tapering, incurved arm-, margins dentate; ends 

 convex bearing sis oblong teeth arranged in crown-form; 

 viewed from the vertex, sis radiate, margins delicately serrate- 

 dentate, apices tridentate. 



I Hameter 7585 ". 



Denmark pond, Passaic County, and pond near Malaga, 

 New Jersey. 



This species has the crown teeth of St. Rotula, but not the 

 size, number of arm.-, nor the serration. 



Var. Floridense, Wolle. Plate XLIII, figs. 12, 13, 14. 



This form lias points in common with the present species, with 

 St. Ophiura,a.nd with St. pentadadvm ; buttheform recognized 



under the latter name i- very slender and usually smaller; 

 St. Ophiura has -even arm.-, long, and coarsely dentate-serrate. 

 Size, relative length of arm- and breadth of body, and the 

 marginal serration and crown papilla; or teeth, make it appear 

 most nearly allied to the present specie-. 



Diameter 75-85 /'.; exception- 50 fi. 



Frequent in pond water, Florida. 



