430 DIATOMACE^. 



Navicula phcenicenteron Ehr., Die Infus. p. 175. t. xiii. 

 fig. 1. ft. 



Hab. Cheshunt : A. H. H. Var. 8. Gardener Street : 

 Mr. Jenncr. 



It is possible that the variety ft of Ehrenberg, which is that 

 here described under the name of N. phcenicenteron, is really 

 distinct. The frustule is not transversely striated, but several 

 longitudinal lines may frequently be noticed running along 

 the centre of each. 



2. NAVICULA PALEA Hass. 

 Plate CII. Fig. 10. 



Char. Frustules small, smooth. In front view attenuated, 

 with truncate extremities ; in side aspect lanceolate. 



Navicula gracilis Ehr., Die Infus. p. 176. t. xiii. fig. 2. 

 Frustulia gracilis Jenner, in Flora of Tunbridge Wells, 

 p. 204. Cymbella avenacea Breb. et Godey. 



Hab. Cheshunt : A. H. H. In the great bog near Forest 

 Row ; bogs at Fisher's Castle, &c. : Mr. Jenner. 



This species resembles N. phoznicenteron in miniature. 



3. NAVICULA AMPHISB^NA Bory. 

 Plate CII. Fig. 5. 



Char. Frustules elongated. In front view quadrangular, 

 with straight sides ; in lateral aspect oval, prolonged at 

 each end into a blunt process. 



Navicula amphisbana Bory, Encycl. Meth. 1824. Navi- 

 cula amphisbcena Turpin, Diction, des Sc. Nat. 1828. 

 N. ventricosa, Abhandl. der Akademie d. Wissensch. zu 

 Berlin, 1830, p. 67. N. amphisbcena, Abhandl. &c. 

 1833 (1832), p. 254. Frustulia cuspidata Kiitz., Lin- 

 nrca, 1833, p. 549. t, xiv. fig. 26. N. amphisbana, Die 

 Infus. p. 178. t. xiii. f. 7. Cymbella appendiculata 

 Godey et Breb. 



