OF THE SURIRELLE^. 



-83 



an affinity, rather proves it does not exist. In the Closteria, division takes 

 place across the lunate frond, or in the shortest diameter, whilst in this genus 

 it occurs in the opposite direction. 



Cesatoneis hngissima (Breb.). — 

 Valves lanceolate, with very long sti'aight 

 slender awns, a subcentral keel, a single 

 row of puncta, and obscure striae. KSA. 

 p. 891. = Kitzschia birostmta, SBD. 

 i. p. 42, pi. 14. £ 119. Marine. France, 

 Eno:land. Front view straight, with 



lanceolate middle, and 



long, 



linear, 



truncated beaks, (iv. 22.) 



C. Closterium (E.). — Front view arcu- 

 ate, with lanceolate middle, and long, 

 filifomi, incurved awns ; valves faintly 

 striated, with central keel and a single 

 row of puncta. Ehr. leb. Kreidethierchen. 

 t. 4. f. 7. = Nitzsclda Closterium, SBD. 

 i. p. 42, pi. 15. f 120. Europe, (xii. 59.) 



C. reversa (Sm.). — Front view lanceo- 

 late, with loug beaks, the extremities 

 of which are bent in opposite direc- 

 tions ; puncta obsolete ; stiise obscure, 

 48 in -001". = Nitzschia reversa, 

 SBD. i. p. 4.3, pi. 15. f. 121. Brackish 

 Avater. Europe. 



C. s])iralis (K.). — Lanceolate, with 

 long, flat, spirallv-twisted beaks. KB. p. 

 104; t. 4. f. 38. Marine. Europe, (xin. 9.) 



C. suhulata (Breb.). — Lanceolate su- 

 bidate, very slender, smooth, gTadually 

 tapering into slender beaks, which are 

 sometimes straight, sometimes cmwed or 

 sigmoid. KSA. p. 89. Marine. France. 



C. acicidaris (K.). — Front view narrow 

 linear ; valves lanceolate, with straight, 

 slender beak ; striae obscure. = Synedra 

 acicidaris, KB. p. 68, t. 4. £ 3; Nitzsclda 

 acicidaris, SBD. p. 43, pi. 15. f 122. Fresh 

 water. Em'ope. 



C. gracilis (Breb.). — Elongated, very 

 slender, linear, with rather obtuse 

 straight, cmwed, or sigmoid beaks ; striae 

 obscure. KSA. p. 89. = Nitzsclda T(Bnia, 

 SBD. p. 43, pi. 15. f. 123. Fresh or brack- 

 ish water. Em-ope. 



Douhtfid Species. 



C. CretcB (E.). — Smooth, na\dcular, 

 very slightly constricted at the middle, 

 wdth acute, sti*aight, not much produced 

 apices. ERBA. 1844 ; Microg. pi. 22. 

 £ 61. Fossil. Sicily. The figure shows 

 a distinct median line and nodule. 



C. knninaris (E.). — Broadly lanceolate, 

 with striated margins and short rostrate 

 apices. EA. t. 3. 7. £ 24. Asia and 

 America. A'alve with median line and 

 centi-al nodide. 



C. Linea. = Synedra Linea, EM. pi. 18. 

 £ 78. Fossil. Virginia. Lanceolate, with 

 punctated margins, and naiTow-linear, 

 rostrate ends. 



C. rhomhoides (E.). — India. 



Genus AMPHIPLEURA (Kiitz.). — Fnistnles simple, elongated; valves 

 with longitudinal ridges. An iU-defined genus, the species of which differ 

 considerably in their appearance. 



straight: valves slightly sigmoid. KB. 

 p. 104, t. 4.£ 30. = Ainphipleura sigmoidea, 

 SBD. i. p. 45, pi. 15. £ 128. Marine. 

 Europe, (xiii. 2.) It forms brown 

 stain-like patches on marine rocks, and 

 scarcely changes colom- when gathered. 



A. infiexa (Breb.). — Valves linear. In- 

 nately curved, slightly attenuated, some- 

 what constricted beneath the rounded 

 apices. KSA. p. 88. Marine, (iv. 31.) 

 France and Britain. 1-430" to 1-336". 

 Striae close, usually very indistinct. In 

 mode of growth and colour it resembles 

 A. rigida, but changes to a green coloiu" 

 as soon as gathered. 



Amphipleura pellucida (K.). — Frus- 

 tules slender, hyaline ; valves narrow 

 lanceolate, with rather obtuse apices. 

 KB. p. 103, t. 3. £ 32 : SBD. pi. 15. £ 127. 

 = Naiicida pellucida, Ehr In£ t. 13; 

 Aulacocystis jjellucida, Hass Algae, p. 427, 

 pi. 102. £ 8. Fresh water. Europe. 

 (IV. 30, IX. 140 & xm. 1.) 1-300" to 

 1-140". Frustides often connected in 

 flat, longitudinal band-like series by a 

 mucous covering. 



A. Dauica (K.). — Lanceolate, obtuse 

 or truncated, smooth. KB. p. 10-3, t. 30. 

 £ 38. Marine. Em-ope. 1-390". 



A. 7'igida (K.). — Elongated, linear 

 lanceolate, \\itli truncate ends: front view 



FAMILY Y.— SUEIEELLE^. 



Fnistnles prismatic or subdisciform ; striae of the lateral surfaces either 

 interrupted by a longitudinal line or radiate. The SuriiTlleae comprise by no 



