STAURASTUUM. 149 



ends convex, bearing six oblong teeth arranged in crown- 

 form; viewed from the vertex, six radiate, margins delicately 

 serrate-dentate, apices tridentate. 

 Diameter 75-85 ^. 



Denmark Pond, Passaic County, and pond near Malaga, 

 New Jersey. 



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

 size, numher of arms, nor the serration. 



Yar. FLORIDENSE, Wolle. Plate LIV, figs. 12, 13, 14. 



This form has points in common with the present species, 

 with St. Ophiura, with St. pentacladum ; but the form recog- 

 nized under the latter name is very slender and usually 

 smaller; St. Ophiura has seven arms, long, and coarsely den- 

 tate-serrate. Size, relative length of arms and breadth of 

 body, and the marginal serration and crown papillae or teeth, 

 make it appear most nearly allied to the present species. 



Diameter 75-85 //. ; exceptions 50 //. 

 Frequent in pond water, Florida. 



ST. PENTACLADUM, Wolle. Plate LIV, fig. 15 ; Plate LV. figs. 



15, 16. 



Of the same general type as the preceding. It has five 

 rays, end view, but these are more slender, the body is 

 smaller and the apices are more spreading. 

 Diameter 40-70 //. 



Gilder Pond, Mt. Everett, Mass., and in waters scattered 

 throughout New Jersey and Pennsylvania. 



ST. LEPTOCLADUM, Nord. Plate LV, figs. 4, 5. 



Semi -cells subtriangular, end broadly rounded, furnished 

 with small rudimentary teeth ; within the margin a small 

 tumor; margins serrate-crenate ; base truncate, superior 

 angles produced laterally, each into a long, thin, incurved, 

 granularly rough arm with a bi-tri -furcate apex ; in vertical 

 view, fusiform with an obtuse angled inflation in the middle. 

 Diameter 80-100 yu. ; length about 25 //. 



The original, typical plant from Brazil, is described by the 

 author, and figured by him with the arms strongly incurved 

 and body longer than our form. The plants identified as of 

 this species, have the arms nearly horizontal, and often 

 strongly recurved. 



They occur frequently in ponds of New Jersey, Massachu- 

 setts, Minnesota, Pennsylvania, Florida and doubtless in 

 many other States. 



