BRITISH DIATOMACE/E. 6/ 



17. Pleurosigma distortum, W. Sm. V. lanceolate, abruptly bent 

 towards the obtuse extremities ; colour pale pink ; " trans, striae 75 

 in -001"; long, striai 65 in -001"." (R. B.) Length -0026" to -0042". 

 v.v. 



W. Sm. Ann. 2nd Ser. vol. ix. p. 7. pl.i. 10, Prit. Anim. xix. 10. 



Marine. Coast of Sussex, Aug. 1850, W. Sm. Folkestone, Mr. Capron. 

 Plate XX. 210. 



18. Pleurosigma Fasciola, W. Sm, V. lanceolate, extremities pro- 

 duced, flexure considerable ; colour pale pink ; trans, striae 64 in 

 •001". Length -0036" to '0048". v.v. 



jS. Extremities abruptly bent. 



Ceratoneis Fasciola, Kiitz. Bacill. iv. 4. 



Marine. Belfast Bay, Aug. 1849. Poole Bay, Sept. 1850. Hastings, 

 Nov. 1851, W. Sm. Hull, Mr. R. Harrison. 



Plate XXI. 211. Var. /3. 211 a'. 



19. Pleurosigma macrum, n. sp. V. lanceolate, extremities pro- 

 duced, flexure terminal, moderate; "trans, striae 85 in'OOl"." (R. B.) 

 Length -0083" to -0106". v.v. 



Brackish water. Iford, Sussex, Oct. 1852, W. Sm. 

 Supp. Plate XXXI. 276. 



20. Pleurosigma prolongatum, W. Sm. V. lanceolate, narrow, 

 acute, flexure moderate ; " trans, striae 65 in -001".^' (R. B.) Length 

 •0043" to •0060". v.v. 



W. Sm. Ann. 2nd Ser. vol. ix. p. 9. pi. ii. 7. Prit. Anim. xx. 7. 

 Marine. Poole Bay, Oct. 1849. Shoreham, Sept. 1852, W. Sm. 

 Plate XXII. 212. 



21. Pleurosigma tenuissimum, n. sp. V. very narrow, linear-lan- 

 ceolate, acute, flexure considerable ; striae 48 in •OOl". v.s. 



Brackish water. Walton, Essex, Mr. Topping, April 1852. 

 Plate XXII. 213. 



22. Pleurosigma littorale, W. Sm. V. broadly lanceolate, acute, 

 flexure considerable; colour purplish; long, striae 24 in "OOl"; 

 trans, striae 50 in -QOl". Length -0046" to -0063". v.v. 



F 2 



