36 BRITISH DIATOM ACE.E. 



4. Tryblionella punctata, n. sp. V. elliptical, acuminate, striated ; 

 strise moniliform, 31 in *00l"; canaliculi obsolete. Length -0012" 

 to -0021". v.v. 



Marine. Coast of Sussex, sparingly, Sept. 1850, W. Sm. 

 Plate X. 76. a'. Supp. Plate XXX. 261. 



5. Tryblionella acuminata, n. sp. V. linear, acuminate; canaliculi 

 obscure ; striae delicate, 40 in "OOl", interrupted ; alae obsolete. 

 Length -0025" to -0042". v.s. 



Marine and brackish water. Poole Bay, June 1849; Belfast Bay, Sept. 

 1849; near Lewes, Dec. 1850, W. Sm. 



Plate X. 77. 



6. Tryblionella angustata, n. sp. V. as in the last species ; striae 

 continuous, 36 in -001". Length -0021" to -0040". v.v. 



Freshwater. Iford, Sussex, Oct. 1852, W. Sm. Guildford, Mr. Capron. 

 Supp. Plate XXX. 262. 



Genus 15. CYMATOPLEURA, W. Sm. 



Frustule free, oblong, or elliptical ; valves undulated. 



The undulations of the surface of the valves separate the present 

 genus from both the last ; the absence of alae and canaliculi are further 

 characters which leave no room for hesitation as to its distinctness. 



1. Cjrmatopleura Solea, TV. Sm. F. V. oblong, hnear; V. fiddle- 

 shaped, symmetrically divided by a central sinus on each margin ; 

 undulations six ; surface of V. striated ; striae 18 in '001". Length 

 •0042" to -0115". v.v. 



W. Sm. Ann. 2nd Ser. vol. vii. pi. iii. 9. NavicuJa librilis, Ehr. Inf. xiii. 22. 

 Prit. Anim. xviii. 9. Surirella Solea, Kiitz. Bacill. iii. 61. Sphincfo- 

 ci/stis librilis, Hass. Alg. cii. 3. 



Freshwater: common. Lewes, May 1850, and Oct. 1852, &c., TV. Sm. 



Plate X. 78. Frustule with endochrome, Frontispiece, fig. LXXVIII. 



