76 BRITISH DIATOMACE.E. 



much divided, fasciculated, and fastigiate above ; frustules in nume- 

 rous closely-set files; valve elliptico-lanceolate, acute; striae 40 

 in -001". Length of frond l". Length of frustule -0015" to -0022". 

 Breadth of valve *0003". v.v. 



Ag. Consp. p. 18. ad specimina authentica in herb. Grev. Grev. S. C. F. 

 tab. 298. Grev. B. F. p. 413. Harv. Man. p. 211. ad specim. authen. 

 Kiitz. Bacill. xxvii. 5. ad specimina quse dedit. cl. De Brebisson. 



Marine : on rocks. Torbay, Mrs. Griffiths and Mrs. Wyatt. Swanage, 

 Dorsetshire, March 1849; "Newhaven, Sussex, Oct. 1853, &c, W. Sm. 

 Burntisland Sands, and Joppa near Edinburgh, Oct. 1853, Dr. Greville. 

 Sidmouth and Exmouth, Miss Cutler. 



Plate LVII. 362. 



7. Schizonema torquatum, W. Sm. Frond filiform, simple below, 

 much divided, and fasciculated above, ultimate divisions exceed- 

 ingly twisted ; frustules subdistant, in numerous files ; valve lan- 

 ceolate; striae 40 in •001". Length of frond r5". Length of frus- 

 tule -0009" to -0012". Breadth of valve -00035". v.v. 



Schizonema Smithii j3. torquatum, Harv. Man. p. 2 1 1 . ad specimina authentica. 



Marine : on rocks, or larger Algse. Torbay, Mrs. Griffiths. Poole Bay, 

 Sept. 1849, W. Sm. Exmouth, June 1854, Miss Cutler. Joppa near Edin- 

 burgh, Dr. Greville. 



It is not improbable, as Dr. Harvey suggests, that the present species is a 

 variety of S. Smithii ; but as the contorted character of its ultimate ramuli 

 gives it a very characteristic appearance, and its frustules are shorter and more 

 slender than those of S. Smithii, I have thought it better to figure and 

 describe it as distinct. 



Plate LVII. 361. 



8. Schizonema divergens, n. sp. Frond simple below, sparingly 

 divided, or by cohesion irregularly submembranous above ; ulti- 

 mate ramuli short, obtuse ; striae 42 in -001". Length of frond l". 

 Length of frustule -0013" to -0018". Breadth of valve -00035". v.s. 



Marine. Lame Lough, in five fathoms, Sept. 1 853, Dr. Dickie. 



The specimens supplied by the discoverer were remarkable for the diffused 

 arrangement of the primary divisions ; hence the name I have adopted : the 

 species is closely allied to the last two. 



Plate LVII. 363. 



