BRITISH DIATOMACEiE. 75 



The valves are often somewhat acute, and not with rounded apices as in the 

 figure. 



Plate LVI. 355. 



3. Schizonema comoides, Ag. Frond filiform, simple below, much 

 divided and fasciculated above ; frustules crowded ; valves lanceo- 

 late; striae 48 in -001". Length of frond -5" to L5". Length of 

 frustule -0008" to -0013". v.v. 



Ag. Consp. p. 19. Harv. Man. p. 213. ad specim. authen. 



Marine : on rocks, or mud hanks. Torbay, Mrs. Griffiths. Aberdeen, 

 Br. Dickie. Coast of Sussex, March 1854, W. Sm. 



Plate LVII. 358. 



4. Schizonema confertum, n. sp. Frond filiform, sparingly divided 

 throughout; frustules exceedingly crowded; valves lanceolate, 

 acute ; striae marginal, indistinct. Length of frond *l". Length 

 of frustule -0008" to -001 1". v.s. 



Schizonema implicatum, Harv. sic Dr. Dickie in lit. 



Marine. Aberdeen, Dr. Dickie. 



This is certainly not S. implicatum, Harv., the valves being different both 

 in form and striation. 



Plate LVII. 359. 



5. Schizonema mucosum, Kiitz. Frond filiform, gelatinous, simple 

 below, by cohesion submembranous above, margin irregularly 

 ramulous; frustules in files, few, subdistant; valve elliptical, deli- 

 cately striated. Length of frond *2". Length of frustule •0009' / 

 to -0013". v.v. 



Kiitz. Bacill. p. 115. tab. xxvi. 9. 



Marine : in muddy pools. Hove, near Brighton, April 1854, W. Sm. 



I cannot refer this species to any in the ' Manual,' and have ventured to 

 adopt Kiitzing's name, as my specimens coincide in most particulars with the 

 description and figure of S. mucosum given in the ' Bacillarien.' 



Plate LVII. 360. 



6. Schizonema Smithii, Ag. Frond filiform, robust, simple below, 



