430 DIATOMACEiE. 



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

 fig. 1. /?. 



Hah. Cheshunt : A. H. H. — Var. B. Gardener Street : 

 Mr. Jenner. 



It Is possible that the variety (B of Ehrenberg, which is that 

 here described under the name of N. phcenicenteroriy 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. xiil. fig. 2. 

 Frustidia gracilis Jenner, in Flora of Tuubridge Wells, 

 p. 204. Cymbella avenacca Breb. et Godey. 

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

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



This species resembles N. phoenicenteron 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 hlunt process. 

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

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

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

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

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

 nsea, 1833, p. 549. t. xiv. fig. 26. N. amphishcena, Die 

 Infus. p. 178. t. xiil. f. 7. Cymhella appendiculata 

 Godey et Breb. 



