BRITISH DIATOMACE^. 79 



3. Gomphonema acuminatum, Ehr. F. V. cuneate, slightly in- 

 flated at centre, and crested at the upper extremity ; V. constricted 

 triangular and apiculate above, attenuated below ; striae 24 in •001". 

 Length -0011" to -0028". v.v. 



/3. V. much elongated and slightly constricted below. Length "003 1" to 

 •0042". 



y. V. cuneate at larger extremity, constriction often obsolete. 



Ehr. Inf. xnii. 4. Kiitz. Bacill. xiii. 3. ad specim. quae dedit amic. De Brc- 

 bisson. Prit. Anim. xvi. 23. Hass. Alg. xcix. 1. Gomp. minutmn, 

 Ralfs, Ann. vol. xii. pi. xviii. 5. 



Var. ft. Gomp. coronatum, Kiitz. Bacill. xxi. 12. 



Freshwater: frequent. Lewes, Nov. 1851, W.Sm. Lough Mourne and 

 Peterhead Deposits. Var. ft. Dolgelly Earth. Rescobie, Mr. P. Grant. 

 Var.y. Lewes, Feb. 1853, &c. W. Sm. (San Fiore, Italy. Little Falls, New York.) 



Plate XXVIII. 238. a. a', & b. Var. ft. 238 ft. Var. y. 238 a" & a'". 



4. Gomphonema cristatum, Ralfs. F. V. obovate, crested ; V. ob- 

 ovate, apiculate ; lower extremity acute ; striae 24 in '001 ". Length 

 •0009" to -0022". v.v. 



Ralfs, Ann. vol. xii. pi. xviii. 6. Hass. Alg. c. 1. Gomp. Augur, Kiitz. Bacill. 

 xxix. 74 ? 



Fresh water. Shoreham, Kent, Dec. 1842; Farnham, Surrey, Jan. 1844, 

 Mr. Jenner. Pond, St. James's Park, London, Jan. 1852, 3Ir. ShadboU. 



Plate XXVIII. 239. Frustules with endochrome. Frontispiece, 

 fig. CCXXXIX. 



5. Gomphonema dichotomum, Kiitz. F.V. slightly cuneate, trun- 

 cated; V. lanceolate, acute; striae 34 in -001". Length "0011" to 

 •0018". v.v. 



ft. Stipes incrassate ; frustules flabellate, obtuse. 



Ralfs, Ana. vol, xii. pi. xviii. 7. Kiitz. Bacill. viii. 14. Hass. Alg. xcix. 2. 

 Gomp. minuticm, Ag. Cousp. p. 34. ex specim. authen. quee communi- 

 cavit cl. Dr. Greville. Gomp. gracile, Ehr. Inf. xviii. 3. 



Fresh water. Wareham, Jan. 1850. Penzance, Mr. Ralfs. Marl, Co. 

 Down. Premnay Peat. Var. ft. Plumpton, Sussex, Apr. 1852, W. Sm. 



Plate XXVIII. 240. Var. ft. 240 ft. Frustules with endochrome, Frontis- 

 piece, fig. CCXL. 



