268 DESCRIPTION OF \^Poli/gastrica 



with a short process on each side, termiuatcd by miiuite sjwnes ; end 

 "\dew with thi-ee to five straight rays, terminated by spines. Length 

 1 -666th. 



Statjeasteum spinosum. — Constriction deep ; segments elliptic, fur- 

 nished with a few bifid spines ; lateral spines solitary, larger and more 

 forked ; end view triangular, with two to three spines on each side, 

 and one terminating each angle. Sporangia orbicular, with nume- 

 rous elongated spines, forked at the apex. M. Brebisson considers 

 this identical A^vdth Xanthidium furcatum, (Ehr.) Length l-859th. 



S. vestitum. — Eough, with minute emarginate spines; segments 

 fusiform ; end view tri-radiatc, each side having two spines, short, 

 slender, and often accompanied by other smaller ones. 



Its most distinctive character is the presence of the pair of slender 

 forked spines at the middle of each margin. Length l-625th. 



S. pygmmmx (Breb.) — Segments cuneiform ; end view triangular, 

 with slightly rounded sides. It is smaller than S. alternans, its 

 sides, in the end view, are more convex, and its angles less rounded. 

 The sporangium is orbicular and spinous. 



S. ruguhsum (Breb.) — Segments elliptic, denticulate at theii' 

 sides ; end view triangular, with the angles broadly rounded and 

 denticulate. 



S. seahnim (Breb.) — Segments elliptic, scabrous ; end \'iew tri- 

 angular, fiinged with minute emarginate spines. 



S. hacillare (Breb.) — Smooth ; processes capitate ; end view with 

 three to five capitate rays or processes. Processes in front view 

 stout ; divergent. 



S. capitulum (Breb.) — Segments quadrate, sinuated on each side, 

 prominences rough ; end view triangular, with broadly rounded 

 angles. Central constriction of frond shallow ; the prominences of 

 segments arc rough, with minute granules, which give them a crenate 

 appearance. End margin straight. 



S. pileolattim (Breb.) — Quadrilateral, twice as long as broad, 

 slightly constricted at the middle ; segments quadrate, tenninated 

 by three conical processes, rough, with minute granules. End view 

 triangular, angles rounded. 



