150 PESMIPS OF THE UNITED STATES. 



St. Kitcheeii. Wolle. Plate XL, figs. 35, 36. 



Cells smooth, about as long as wide; semicellssubelliptic, bases 

 more inflated than the ends, the angles produced into bifurcate 

 processes; semicells furnished with three additional processes; 

 end view triangular, angle- produced, apices bisected ; <>n the 

 top surface three bifurcate processes, one extending over each 

 of the three sides; membrane smooth or finely punctate. 

 Diameter 38-50 ft. 



Collected by Rev. H. D. Kitchel, in Gilder Pond, Mount 

 Lverett, Mass. 



St. 8pinosum, Halt's, bears some similarity but i> separated 

 by having two or more spines on each side, beside the one 

 terminating each angle. St. fureatum, Lhrb.. also appears 

 related, but i> possessed "t' more spines. 



St. furcatdm, (Ehrb.) Breb. Plate XL. figs. in. n. Plate 

 XL VIII, figs. 15, Pi. Plate LI I. tig. 34. 

 ('ell- smooth about as long a- wide, sometimes shorter, fur- 

 nished with numerous processes always more or less widely 

 furcate at the a pice- ; cud view triangular, angles somewhat 

 produced and furcate: sides each with two, or rarely three, 

 furcate processes; normally a semicell has nine processes, one al 

 each angle and two on each side between the angles; in front 

 view, more or less broadly elliptic, angles draw n oul and furcate ; 

 the end margin ha- u-uall\ four processes visible, projecting 

 over the margin. 



A variable form separated from furcigerum, eu&ephanum 

 and others not only by the smooth, or punctate membrane, 

 which is very striking in contrast with the granular surface, 

 and serrate margins of the others, but by the processes, par- 

 ticularly evident in end view, which do not spring from the 

 upper surface more less distant within the margin, lint from 

 the margin itself. This feature not evident in St. pseudofur- 

 cigerwn, Reinsch, gives it a position for itself. The form 

 Plate XLI, figs. 8, 9, from Minneapolis, Minn., is Ralfs' St. 

 spinosum, now properly transferred to this " old name," has 

 beside the marginal processes some smaller accessory ones 

 within the margin, Plate LII, fig. 34. Plate LII, figs. 25, 26, 

 is another variety from the same locality of unusual size and 

 very marked in the wide-spreading forks of the processes ; 

 Ralfs admits of " sometimes three marginal-spines as seen in 

 end view " 



