47S DESCRIPTION OP {Poli/ffasirica. 



Stnedea faseiculata. — Smaller, smooth, attenuated near the ex- 

 tremities, which are sub- acute; laterally linear. In front view, elliptic 

 lanceolate, marine, growing on seaweeds. (l-800th to 1 -480th.) 



S. hmaris. — Smooth, arcuate (curved), ohtuse, linear, aggregated 

 in a radiating form, affixed to Conferva, &c., but sometimes isolated 

 and free. Length 1 -430th to 1 -280th. Common in fresh water. 



S. hilunaris. — Smooth, with two curvatures (bOimate) resembling 

 two lunate bodies attached end to end, base tapering, apex dilated 

 and obtuse. Length l-570th. 



S. gigantea. — Very large, linear, striated laterally, each end sud- 

 denly roimded, dorsally apices attenuate, sub-acute ; surface very 

 finely striated in the intervals of the pinnules. Length l-60th. 

 Oasis of Jupiter Ammon, AMca. 



S. (?) AtistraNs. — Linear, striated ends on every side, attenuate, ob- 

 tuse. Length 1 -432nd. In siliceous schist from the Phillipine Islands. 



S. Semicyclus. — Small, linear, semi-circular, obtuse, with trans- 

 verse strife. Length, diameter taken in the length of its curve, 

 l-1152nd to l-864th. Fossil in Sweden. Is it a fragment of others? 



S. paleacea. — Very narrow, smooth; apices sub-acute. Length 

 l-480th. In siliceous earth from the Phillipine Islands. If a 

 Podosphenia ? or Fragilaria ? 



S. amphirhynchus. — Linear, striated dorsally ; extremities con- 

 stricted, sub-acute, rostrate; no median, hyaline, smooth band. 

 Length 1-1 20th to l-96th. Fresh water. Egypt, Mexico. 



S. Entomon. — Elongate, thick, striate ; oblong on the sides, con- 

 stricted at the middle and obtusely cuneate ; dorsally, broadly linear 

 and truncate. 



S. gihha. — Long, linear, narrow, smooth, fasciculate; laterally 

 widely expanded at the centre, ends gradually tapering, obtuse. 

 United States. 



S. l(Bvu. — Smooth, shorter, but narrowly linear, equally slender 

 throughout, ends gradually tapering, sub-acute. Length 1-130. On 

 marine Algfe. 



S. scalaris. — Broadly linear, large ; sides straight, ends truncate, 

 rounded; delicately striated between the pinnules. Length 1 -288th. 

 Surinam. 



