/«? 



-; 



422 DIATOMACE^. 



Ehr., Die Infus. ; Jeniier, in Flora of Tunbriclge Wells, 

 p. 206. 



;C ^^^' Hah. On aquatic plants in pools and ditches, near Hen- 

 „^^^zii , field : 3Ir. Borrer. Frequent in Sussex : Mr. Jenner. 



^'•■^jT^y^^^ ^^Cheshunt and neighbourhood: A. H. H. Oswestry: 



fj,.f^ ''''w^ ^^^' ^' ^^^'^^l/' Ilfracombe; Swansea; Dolgelly and 

 "^ f^ - Bangor, North Wales : Mr. Rolfs. 



^f: ' / A very distinct little species. The degree of constriction 

 ^^^^^ ofUthe neck varies considerably in different specimens ; and 

 % ^ ^/this circumstance doubtless led to the institution on the part 

 of Ehrenberg of the Gomphonema capitatum, which is as- 

 suredly but a state of G. truncatum. 



3. Gomphonema acuminatum Ehr. 

 Plate XCIX. Fio'. 1. 



Char. Frustules in front view cuneate and truncate. Lateral 

 surfaces constricted, acuminate, striated. 



G. minutum Ag., Conspect. Diatom. 1832, p. 34. ; Grev. 

 in Hook. Br. Flor. vol. ii. p. 410. Gomph. acuminatum, 

 Abhandl. der Akademie d. Wissensch. zu Berlin, 1831, 

 p. 86. ; Bericht. der Akademie d. Wissensch. zu Berlin, 

 1836,"p. 53., 1837, p. 44.; Die Infusor. p. 217. t. xviii. 

 fig. 4. G. minutum Balfs, in Annals, vol. xii. p. 462. 

 pi. xviii. f. 5. ; Jenner, in Flora of Tunbridge Wells, 

 p. 206. 



Hah. Sussex : Mr. Jenner. Cheshunt, &c. : A. H H 

 Barmouth : Rev. T. Salwey. Trengwainton j^onds, 

 near Penzance, and pond on Towednack Moor, near St. 

 Ives ; Dolgelly : Mr. Ralfs. 



The degree of constriction and acumination of the frus- 

 tules Avould appear to be subject to very considerable variation. 

 As the species was published at nearly the same period, by 

 both Agardh and Ehrenberg, and apparently first by Ehren- 

 berg, I have retained the name of the latter which is infi- 

 nitcl)' the more appropriate. 



