284 DESCRIPTION or \^Polygastrica, 



It is larger than S. Hijstrim, its spines more nnmerons, and the end 

 margins, in front view, convex. Length 1 -597th. 



STATJKA.STiirjr Hystrix. — Segments sub-quadrate, sijinous ; end 

 view with 3 to 4 rounded angles, each furnished with a few subu- 

 late spines. Frond smaller than that of any other species with 

 simple spines. End view triangiilar or quadrangular, with concave 

 sides and rounded angles. Length l-1075th to 1 -1020th. 



(D.) — £nd view of frond showing four or more toothed hies, which 

 a/re either truncate or rounded, lut never elongated into rags. 



S. quadrangulare. — Smooth; segments quadrangular, with a few 

 marginal spines or teeth ; end view quadrilateral, with truncate 

 angles either emarginate or dentate. Length l-1157th. 



S. sexcostatum. — Large, rough with conic granules which give 

 a dentate appearance ; segments in fi'ont view with a toothed angle 

 at each side ; end view cii'cular, with 5 to 6 broad, short-toothed 

 lobes. The transverse view has a large central opening, sur- 

 rounded by a row of large granules. Length 1-66 1st. 



(E.) — Frond smooth ; end view acutely triangular ; with two accessory 

 subulate spines to each angle. 



S. monticuhsum. — Eather large segments with a forked spine on 

 each side, and at the end about four short, stout, acute projections ; 

 end view acutely triangular, with a bifid appendage to each angle. 

 Very rare. 



S. pungens. — Each end with about sis subulate spines, directed 

 outwards ; each angle in the end view tapering into a spine, which 

 has two smaller ones at its base. Its spines are more slender than 

 those of S. monticuJosimi, and in the front view are all simple and 

 directed outwards. Eare. 



(F.) — Frond smooth; front view witli diverging processes divided at 

 the apex. 



S. Irachiatum. — Minute ; front view with thick diverging processes, 

 deeply bifid or trifid at the apex ; end view with 3 to 4 rays. Frond 

 scarcely constricted at the middle. Sporangia quadrate and spinous. 

 Length 1-1 11 1th. 



S. Iceve. — Minute, smooth ; segments with short processes, foi'ked 

 at the apex and directed outwards ; end view with 3 to 4 bipartite 

 angles ; deeply constricted at the middle, thus difFeiing fr-om S. 



