STAUEASTRXJM. 161 



Section IV.— Cells furnished with numerous processes usually divided at the 

 ends. 



St. puecigeeum, Breb. Plate LIX, figs. 12-14 ; Plate LXIII, 

 figs. 23, 24. 



Cells constricted at the middle, angular, with six processes 

 to each semi- cell; in end view, triangular, one process at 

 each angle and one within the angle, about half way between 

 it and the center of the triangle, Plate LIX, fig. 12, Plate 

 LXIII, fig. 24; semi-cell in front view somewhat elliptic, 

 Plate LIX, fig. 13 ; Plate LXIII, fig. 23 ; each end drawn 

 out into a short process, margins serrate, ends furcate or 

 toothed ; three other processes are usually in view, two on 

 the end margin, and one intermediate. Cytioderm granular; 

 granules arranged in transverse lines. 



Diameter 50-62 fx. 



Occurs in many localities, Rhode Island and soutliward to 

 South Carolina and Florida. 



Foreign authors report a form, quadrangular in end view ; 

 such would have eight processes to a serai-cell. 



I find considei-able diversity in the specimens of this species, 

 particularly in the arrangement of the processes on the tops 

 or ends of the cells ; typically they are attached away from 

 the center, and are directed towards the angles ; a variety 

 (Plate LIX, fig. 14), has them coming from the center and 

 directed transversely, or at right angles with the sides. 



St. bustephanum, (Ehrb. ), Ralfs. Plate LIX, figs. 9-11. 



Of nearly equal length and breadth, granular, margins 

 more or less serrate; semi-cells elliptic (fig. 9) with angles 

 produced, furcate; end view triangular, furnished with nine 

 processes, counting the three somewhat produced, and bi- 

 furcate angles ; the other six are on the upper surface, 

 attached,' usually between the center and the margins, ends 

 elevated above the surface ; the processes extend to margins, 

 or slightly over them ; in front view, these present them- 

 selves on the outer margin in two pairs ; the third pair is 

 either under the cell, or stands towards the eye, and is in- 

 visible. 



Diameter varies from 50-75 jx. 



Var. a. fig. 11 represents a form with more elongated 

 processes. 



Yar. &. figs. 4-6 is another variety, very distinct; it is 

 smaller in size and has spreading, swallowtail-like ends of 

 processes. 



11 



