Frustulia.] AhQJE DIATOM ACEjE. 251 



verse granular yellow mass. Grev. — Grev. in Hook. Br. Fl. 

 v. ii. p. 406. Lyngb. Hyd. Ban. p. 110. t. 62. 



Parasitic on small Algse in the sea, very common ; investing them 

 with a dense pulverulent covering. 



5. D. elongatum, Ag. Elongated Diatoma. Filaments with 



a longitudinal line, the joints ten times longer than they are j 



broad. Grev Grev. in Hook. Br. Fl. v. ii. p. 407. Berk. 



Brit. Jig. p. 21. t. & 



In pools and ditches, scattered among various Conferva. Near 

 Limerick ; W. H. Harvey. 



6. D. flocculosum, Ag. Flocculose Diatoma. Filaments 

 with a longitudinal pellucid line, the joints transversely striated, 

 nearly equal in length and breadth. Grev. — Grev. in Hook. Br. 

 Fl. v. ii. p. 407. —Conf.flocculosa, Dillw. t. 28. E. Bot. t. 1761. 



Pools, ditches, &c. ; parasitic on various Confervas. 



* if. * Frustula fasciculate or fiabelliform. 



7. D. fasciculatum, Ag. Fasciculated Diatoma. Frustula 

 linear, somewhat acuminate at each extremity. Grev. — Grev. 

 in Hook. Br. Fl. v.'\\. p. 407. — Echinella fasciculata, Grev. 

 Crypt. Fit. 16./. 1—3. 



On marine Algse, frequent. 



8. D. truncatum, Grev. Truncate Diatoma. Frustula linear, 

 truncate at the extremity. Grev. — Grev. in Hook. Br. Fl. v. ii. 

 p. 487. — Echinella fasciculata, /3. Grev. Crypt, t. 16. /. 4. 



Pools and ditches, on various Conferva, common. 



92. Frustulia. Ag. Frustulia. 



Frustula linear, free or imbedded in a shapeless mass, solitary 

 or binate. Grev. — Name, frustula, fragments, of which this 

 plant is wholly composed. 



1. Y.fasciata, Ag. Banded Frustulia. Frustula 8 — 10 times 

 longer than broad, binate or solitary, obtuse, terminated at each 

 end by a hyaline globule ; dull ochre with a hyaline central 

 band. Ag. Conspect. Crit. Diat. p. 45. 



In fresh water, mixed with other Algae. Plassey ; W. H. Harvey. 



2. F. Ulna, Ag. Acicular Frustulia. Frustula linear, ex- 

 ceedingly slender, acicular, obtuse, marked with interrupted 

 ochraceous bands. Ag. Consp. Crit. Diat. p. 45. 



In fresh water, mixed with other Algae. Plassey, near Limerick ; 

 W. H. Harvey. The frustula are often of an uniform ochraceous 

 colour, except the apices, which are always hyaline. 



