130 BRITISH DESMIDIE.E. 



***** Frond smooth ; end view acutely triangular, with two accessory 

 subulate sjiines to each angle. 



16. S. monticulosmn (Breb.) ; 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. 



Staurastrum monticulosum, Brebisson, Menegh. Synop. Besmid. in Linncpa 



1840, p. 226. 

 Phycastrum monticulosum, Kiitzing, Phycoloyia Germanica, p. 138 (1845). 



Penzance ; very rare, t7. jR. 



Falaise, Brebisson. 



Frond smooth, rather large, deeply constricted at the middle ; segments 

 somewhat elliptic, with a projection on each side forked like the tail of a 

 swallow. The end margin has generally four remarkable projections, which 

 are stout, twice as long as broad, acute, and look not unlike a cluster of pyra- 

 mids. The end view is triangular, the angles acute. At the base of each 

 angle, on the upper surface, is a bifid projection, the aciite points of which 

 appear on each side. 



Staurastrum monticulosum is a remarkable species, difficult to describe, but 

 easily recognized by its figure*. 



Tab. XXXIV. fig. 9. a. front view of French specimen ; h. end view ; both 

 from drawings by M. de Brebisson. 



17. S. pu7igens (Breb.) ; frond smooth, each end with about six subu- 

 late spines, directed outwards ; each angle in the end view tapering 

 into a spine, which has two smaller ones at its base. 



Euastrum, No. 14, Bailey, Amer. Journ. of Science and Arts, v. 41. p. 297. 



t. l.f. 14? (1841). 

 Staurastrum puny ens, Brebisson, in lit. cum icone (1846). 



Penzance ; rare, J. R. Cross-in-Haud, Sussex, Mr. Jenner. 



Falaise, BrSbisson. "West Point, New York, Bailey. 



Frond smooth, deeply constricted at the middle ; segments externally lu- 

 nate, and having on the outer margin about six subulate spines, the lateral 

 ones being the most conspicuous. The end view has three angles which taper 

 gradually into subulate spines ; its iipper surface has two smaller spines at 

 the base of each angle, which diverge and become visible on opposite sides. 



Staurastrum puny ens agrees with S. monticulosum in having two spines on 

 the up])er surface of each angle ; but its spines are more slender, and in the 

 front view are all simple and directed outwards. 



Tab. XXXIV. fig. 10. a. front view; b, c. end views. 



* " S. monticulosum, Breb., cellulis e dorso triangularibus, apicibus acutis- 

 simis, suprapositione bifidis, prominentia bifido-divaricata breviore, quoque 

 angulo superimposita, promiuentiis in centro confluentibus, a latere ellipticis 

 utrinque bifidis, exterius dentatis." — Meneyhini. 



