Frusiuli".] ALGjE DIATOMACE^E. 407 



equal in length and breadth. — Ag. Syst. Alg. p. 4. Lyngb. 

 Hydroph.Dan.p. 179. £. 61. — Conferva fioccidosa^ Dilliv. Conf. 

 t.2%. E. Bot.t. 1761. 



Fools, ditches and slow streams ; parasitic upon various Conferva. 

 Frequent in Spring and Summer. — Of a pale transparent green under the 

 microscope. 1 he joints vary in their relative length and breadth, even 

 in the same filament. 



Frustida fasciculate or flabeU'tform. 



12. D. crystdllbium, Ag. (chrystalline Diatoma); frustula 

 linear elongated obtuse. — Ag. Syst. Alg. p. 3. — Echinella fasci- 

 culata, Lyngb. Hydroph. Dan. p. 210. t. 70. 



Parasitic on various filiform Atgce, in the sea. Devonshire, Mrs. 

 Griffiths. Appin, Capt.Carmichael. Spring. — Much larger than the two 

 following species. The frustula are of a pale yellow colour, not atten- 

 uated at either extremity, and when dry more or less hyaline and glis- 

 tening in a very beautiful manner, like spun glass. 



13. D.fulgens, Grev. (glittering Diatoma); frustula truncate 

 golden-yellow arising inarlabelliform manner from a chrystalline 

 often elongated base. — Exilaria fulgens, Grev. Crypt. Fl.t. 291. 



Parasitic on various filiform marine Alga; Appin, Capt. Carmichael. 

 Spring and Summer.— According to the views of Agardh, this plant 

 must be a Diatoma ; yet the base, on which the frustula are placed, is 

 often so much elongated, as to represent a broad stipes. 



14. D. fasciculdtum, Ag. (fasciculated Diatoma) ; frustula 

 linear somewhat acuminate at each extremity. — Ag. Syst. Alg. 

 p. 3. — Echinella fasciculala, Grev. Crypt. Fl. t. IS.jigs. 1 — 3. 



Parasitic on the filiform marine Alga, frequent. Spring and Summer. 

 — Of a pale dull-yellow. The frustula are attached to a minute chrys- 

 talline base. 



15. D. truncation, Grev. (trioleate Diatoma); frustula linear 



truncate at the extremity Exilaria trunniln. dnc. Crypt. Fl. 



(synops. p. 37.) — E.fas< iculata, 3. 1. <. t. l&.fc 4. 



Pools and ditches, parasitic on various Confc/ru-, Vauchcria-, &c. 

 Spring and Summer. 



103. FnrsTiLiA. Ag. Frustulia. 



Frustula linear, free or imbedded in a shapeless ma--, soli- 

 tary <»r Innate. Ag. — Name ; frustula. small Cnimba Or frag- 



niriiN. of which a mass of this plant presents an appearance. 



1. V.: ohtus<i. Agi(MffU Frustttli'i); famuli -hurt truncate 



at each extremity about three times longer than they are broad. — 



i \> I hare adopted Profeeeor Agardh'i irrangemenl of the /> 

 I hare retained thhi littl.- rronpe In Hie genut Diatoma. M> own 

 led me formerly t" separate if, ud I have not intii.it.. s.»«n reason* t.. . h 

 them. A patient Investigation <•! the whole, with the allied genera, foreign *■ 

 well ;i>. Bruith, mrald i-- neceeeerj to determiue Ihe qoettkm. 



