MELOSEIRA. 399 



2. MELOSEIRA ORICHALCEA Kutz. 

 Plate XCIII. Figs. 6, 7. 



Char. Filaments rather slender, when recent of a fawn colour. 



Frustules two or three times longer than broad, twice 



divided near the centre. 

 Kiitzing, in Linngea, 1833, p. 71. fig. 68. Gallionella auri- 



chalcea Ehr., Die Infus. p. 168. t. 10. fig. 6. ; Amer. 



Bacil. part 2. p. 5. pi. xi. fig. 4 b. 

 Hab. In ditches and slow streams, Cheshunt : A. H. H. 



Stevenston, Ayrshire : Rev. D. Landsborough. Dol- 



gelly : Mr. Ralfs. 



This species differs from Meloseira varians, with which it 

 might be confounded, in its smaller filaments, different colour, 

 longer frustules, in the double division of these, and especially 

 in the dentated margins, by which M. orichalcea is related to 

 Meloseira arenosa, and which is the only character in common 

 between the two species. The Gallionella distans of Ehr. 

 comes close to this species, if it be not identical with it. 



** Margins of the cells smooth. 



3. MELOSEIRA VARIANS Ag. 



Plate XCIII. Figs. 4, 5. 



Char. Filaments rather thick, dark brown, becoming greenish 

 in drying. Frustules once or once and a half as long as 

 broad, once divided in the centre. 



Ag. Conspect. Diatom, p. 64. ? Kiitz. in Linn^a, p. 71. 

 fig. 69. ; Harv. Br. Alg. p. 195. M. lineata Ag., Syst. 

 p. 8. ; Harv. in Manual, p. 195. Gallionella varians 

 Ehr., Die Infus. t. 10. fig. 4. G. aurichalcea Bailey, 

 Amer. Bacil. part 2. pi. 2. fig. 4 c. Conf. lineata Dillw., 

 p. 44. t. {3 Jurg, Dec. 5. No. 18. Conf. hyemalis Jurg, 

 Dec. No. 17. No. 6. Vesiculifera composita Hassall, in 

 Annals of Nat. Hist. vol. x. p. 394. ; Ralfs, in Annals, 

 vol. xii. p. 350. pi. ix. fig. 5. 



