BRITISH DIATOMACE.K. 49 



Sect. III. Valves elliptical, extremities acute. 



12. Navicula Jennerii, TV. Sm. F. V. oblong ; V. twisted, elliptical ; 

 extremities somewhat acute ; striae very distinct, 30 in "OOl", reach- 

 ing the central line ; colour of dry valve a pale purple. Length 

 •0025" to -0068". v.v. 



Navicula tumida, Breb. in Kiitz. Sp. Alg. p. 77' ad specimina quae communi- 

 cavit cl. De Brebisson in lit. Sept. 1852. 



Marine or brackish water. Rye, Mr. Jenner. Belfast Bay, Aug. 1849, 

 and Coast of Sussex, frequent, Feb. 1852, W. Sm. Menai Straits, Prof. Wil- 

 liamson, July 1852. 



Plate XVI. 134. b. outline of F. V. 



13. WavicTila "Westii, n. sp. F. V. oblong; V. straight, elliptical, 

 acute ; striae delicate, scarcely reaching the central line, 38 in '001" ; 

 colour of dry valve a dark purple. Length '0032" to '0042". v.v. 



Marine: detected by Mr. Tufen West with the last. May 1852. Shore- 

 ham Harbour, Nov. 1852, W. Sm. 



Plate XVI. 135. 



14. Navicula convexa, n. sp. F. V. oblong ; V. twisted, acute ; 

 striae very distinct, 21 in '00 1", not reaching the central line ; dry 

 valve colourless. Length -0048" to -0062". v.v. 



Marine. Coast of Sussex, Sept. 1851. Harwich, Mr. Shadbolt, May 1852. 



Plate XVI. 136. b. outline of F. V. Frustule with endochrome. Fron- 

 tispiece, fig. CXXXVI. 



15. Navicula elegans, n. sp. V. elliptical acuminate ; striae distinct, 

 24 in 'OOl", waved, radiate, absent around the central nodule. 

 Length -0020" to -0032". v.v. 



Marine or brackish water. Poole Bay, June 1849, W. Sm. Cockerham 

 Marsh, Lancashire, 3Ir. Johnson. 



Plate XVI. 137. 



16. Navicula patula, W. Sm. V. elliptical, somewhat acute ; striffi 

 delicate, 36 in "OOl", not reaching the central line; colour of dry 

 valve purple. Length -0030" to -0040". v.s. 



E 



