66 BRITISH DIATOMACE^. 



Marine or brackish water. "Brooks," Lewes, Sept. 1850. Var. /3. in- 

 vesting a sponge, Poole Bay, Nov. 1849, TF. Sm. 



Plate XX. 206. Outline of smaller var. 206 /3. 



Sect. II. Striae transverse and longitudinal. 



14. Pleurosigma Balticum, W. Sm. V. linear, attenuated towards 

 the obtuse extremities, flexure terminal ; colour dark brown ; long, 

 and trans, striae 38 in -001". Length -0083" to -0142". v.v. 



/3. Smaller, more gradually attenuated. 



y. Attenuated throughout ; strite obscure. 



W. Sm. Ann. 2nd Ser. vol. ix. p. 8. pi. ii. 1, 2 & 3. Prit. Anim. iii. 144. 

 XX. 1, 2, 3. Navicula Baltica, Ehr. Inf. pi. xiii. 10. Kiitz. Bacill. iv. 32. 



Marine or brackish water : frequent. Poole Bay, Aug. 1848. Belfast Bay, 

 Aug. 1849. Coast of Sussex, Aug., Sept., Oct. and Nov. 1850, W.Sm. 

 Cockerham Marsh, Lancashire, Oct. 1849, Mr. Johnson. /3. & y. Coast of 

 Sussex, Oct. 1851, W.Sm. 



Plate XXII. 207. Outhne of young (?) specimens, 207 /3. & 207 y. Out- 

 line of F. V. PI. XXIII. 207. Frustule with endochrome. Frontispiece, 

 fig. CCVII. 



15. Pleurosigma Strigilis, W. Sm. V. lanceolate, acute, flexure 

 considerable; colour pale brown; long, strice 40 in '001"; trans, 

 striae 36 in -001". Length -0116" to '0142". v.v. 



W. Sm. Ann. 2nd Ser. vol. ix. p. 8. pl. ii. 4. Prit. Anim. xx. 4. 



Brackish water. Hull, Mr. R. Harrison. Iford, Sussex, Oct. 1852, JJ^. Sm. 

 Plate XXII. 208. 



16. Pleurosigma acuminatum, fF. Sm. V. lanceolate, acute, flex- 

 ure considerable; colour pale brown; long, striae 40 in '001"; 

 trans, striae 52 in -OOl". Length -0050" to -0065". v.v. 



W. Sm. Ann. 2nd Ser. vol. ix. p. 9. pl. ii. 5. Prit. Anim. xx. 5. Navicula 

 Siffina, Ehr. Inf. xiii. 12. Prit. Anim. iii. 146. Kiitz. Bacill. iv. 26. 



Marine. Shoreham Harbour, June 1850, JF. Sm. Menai Straits, Prof. 

 Williamson. Higham, Mr. Shadbolt. Folkestone, Mr. Capi-on, Nov. 1852. 



Plate XXT. 209. 



