BRITISH DIATOMACEiE. 55 



4. Pinntilaria acuminata, n. sp. V. linear, suddenly attenuated 

 towards the acute extremities; costae parallel, not reaching the 

 central line. v.s. 



Fresh water. Premnay Peat. 

 Plate XVIII. 164. 



5. Pinmilaria oblonga, ?F. /Sm. V. lanceolate, extremities rounded ; 

 costae radiate, reaching central line, distant, 11 in '001". Length 

 •0042" to -0066". v.v. 



Navicula macilenta, Ehr. Inf. xxi. 13. Navicula ohlonga, Kxitz. Bacill. iv. 21. 



Fresh water: common. Lewes, Oct. 1852, W. Sm. Belfast, Dr. Dickie, 

 Peterhead Deposit. Marl, Co. Down. 



Plate XVIII. 165. Frustule with endochrome, Frontispiece, fig. CLXV. 



6. Pinnularia cardinalis, Ehr. V. linear, extremities rounded; 

 costae radiate, absent from the centre of V., distant, 9 in 'OOl". 



v.s. 



Stauroneis cardinalis, Kiitz. Bacill. xxix. 10. Prit. Anim. xv. 72. 

 Fresh water. Lough Mourne Deposit. Cantyre Peat. 

 Plate XIX. 166. 



7. Pinnularia lata, W. Sm. V. linear, slightly inflated at the centre ; 

 costae scarcely radiate, not reaching central line, distant, 7 in •001". 

 Length -0025" to -0044". v.v. 



Navicula lata, De Brebisson in lit. cum specim. Kiitz. Sp. Alg. p. 79. 



Fresh water : subalpine. Fell End, Lancashire, at an elevation of 900 feet, 

 Mr. Johnson, May 1851. Snow Mud, on Ben M'= Dhui, at an elevation of 

 3840 feet. Dr. Dickie. 



Plate XVIII. 167. d. outhne of ditto in S. D. 



8. Pinnularia alpina, n. sp. V. elliptical-lanceolate, obtuse ; costae 

 radiate, not reaching central line, distant, 7 to 9 in '001". Length 

 •0038" to -0083". v.s. 



Fresh water: subalpine. Mountains of Aberdeen, Dr. Dickie. Ben M" Dhui, 

 Mr. P. Grant. (Falaise, M. De Brebisson.) 



Plate XVIII. 168. b. outline of F. V. 



