Falklands, etc.] FLORA ANTARCTICA. 519 



6. Dictyocha Ornamentum, Elirb.; I. c. Feb. 1844. 



Hab. Victoria Barrier ; in Pancake Ice. In a floating scum, Lat. 64° S., Long. 1G0° W. 

 Tertiary deposits of Sicily contain tins species. 



7. Dictyocha septenaria, Ehrb. ; I.e. 



Hab. Victoria Barrier; in Pancake Ice, and in mud from 190 fathoms. 

 Previously found fossil in the tertiary deposits of Oran. 



8. Dictyocha Speculum, Ehrb.; Kutz. Kiesel. Bacill. p. 140. t. 21. f. 22. c. 



Hab. Victoria Barrier; in Pancake Ice, and in mud at 190 fathoms. In the stomachs of Salpm, 

 Lat. 66° S., Long. 1 57° W. In a floating scum, Lat. 64° S., Long. 160° W. 



A widely distributed species, found living in the North Sea and Atlantic, fossil at North Africa. Greece, and 

 Sicily, and in Maryland, U.S. 



46. RHIZOSOLENIA, Ehrb. 



1. Rhizosolenia Calyptra, n. sp., Ehrb.; Schrift. Berl. Mad. Hay, 1844. 



Hab. Victoria Barrier; in Pancake Ice. Graham's Land; Gulf of Erebus and Terror, in mud from 

 270 fathoms. 



2. Rhizosolenia Ornithoglossa, n. sp., Ehrb.; I. e. 



Hab. Victoria Barrier ; in Pancake Ice, and in mud from 190 fathoms. Graham's Land ; Gulf of 

 Erebus and Terror, in mud at 270 fathoms. 



Both these species have recently been detected in the Bermuda Islands. 



LVII. DESMIDIEiE, met. recent. 



1. ARTHRODESMUS, Ehrb. 



1. Arthrodesmus Tarda, Ehrb.; Schrift. Berl. Ahad. June, 1841. 

 Hab. Falkland Islands ; on marine Conferva : Lesson. 



LVI1I. LICHENES,* L. 



1. TJSNEA, Ach. 



1. Usnea melaxantha, Ach.; Etch. Univ. p. 618. Syn. Meth. p. 303. Brown, Plant. Spitz, in Scoresby 

 Voy. vol. i. App. p. 76. Kunth. Synops. vol. i. p. 36. If Urv. in Mem. Soc. Linn, Paris, vol.iv. p. 596. 



* Since the publication of the " IAchenes Jntarctici " in the ' London Journal of Botany,' and of those contained 

 in the first part of this work, I have had the advantage of re-studying all the species with my friend, the Rev. Chnrchill 

 Babington, whose profound knowledge of the forms of this difficult order, and acquaintance with the most recent 

 writings of European Lichenologists, have been most liberally brought to bear upon this part of the ' Flora Antarctica.' 



