OF THE SURIRELLE^. 



785 



fascicular, capillary, spuriously jointed; 

 frustules linear, elong-ated, obtuse, 

 smooth. KB. p. Ill, t. 22. f. 11. Ma- 

 rine. Venice. 1-7". 



H. dilatata (K.). — Much branched, se- 

 taceous, branches fastigiate, incrassated 

 aboTe, clavate ; fasciculi closely conti- 

 guous ; frustules linear, elongated, acicu- 

 lar, obtuse. KB. p. Ill, t. 23. f. 1. Ma- 

 rine. Adriatic. 1-12". 



H. moniliformis (Kiitz.). — Capillary ; | 

 branches slender, elongated, moniliform ; j 

 fasciculi of frustules remote ; frustules I 

 very long linear, obtuse. KB. p. 110, 

 t. 22. f. 10. Adriatic, (xiv. 45, 46.) 



H. pumila (Ag., K.). — Ii-regularly di- 

 vided into equal, obsoletely-articulated, 

 capillary branches ; frustules short linear, 

 with rounded ends. KB. p. 110, t. 22. 

 f 9. = Schizonema pumilum, Ag CD. p. 16. 

 Adriatic, (xiv. 37, 38.) 



H. penicillata (Kiitz.). — Fastigiately 

 branched ; branches divaricate, fasti- 



giately di\ided; terminal ramuli white, 

 in pencils; primary tube thick, gelati- 

 nous cartilaginous ; frustules densely ag- 

 gregated, slender, linear acicular, very 

 naiTow. KSA. p. 97. France. • 



H. luhrica (Me., K.). — Gelatinous, 

 green, setaceous, for the most part di- 

 \-ided at the apex; fmstules fascicu- 

 late, densely aggregated, linear. KSA. 

 p. 98. = Schizonema luhriciwi, Menegh. 

 Adriatic. 



_ ll.Jiliformis (S.). — Frond simple; fas- 

 cicles of 3 or 4 frustules ; front view 

 linear-lanceolate, obtuse; valves linear 

 lanceolate, subacute. SBL). ii. p. 80, pi. 

 55. f. 348. Brackish and fresh water. 

 England, (rv. 25.) 



H. sigmoidea (S.). — Frond simple; 

 frustules irregularly fasciculated in bun- 

 dles of about 6 ; front view sigmoid ; 

 valves linear, with attenuated ends. SBD. 

 ii. p. 81, pi. 55. f. 349. Brackish water. 

 Britain, (iv, 26.) 



Genus SYNEDEA (Ehr.). — Frustules elongated, wand-like, attached by 

 the lower end, lateral surfaces equal to or less than the front view, traversed 

 by a smooth median longitudinal line. The true species of Synedi^a are 

 distinguished from all other genera by their wand-like form and attachment 

 by one end. They are usually either fasciculated or fixed to a distinct stipes 

 in a fan-like manner. " As to the organographical considerations which can 

 be instituted in this genus, they reduce themselves to the single one of length 

 predominating over breadth and the eminently bacillary foim derived from it. 

 Thus Kiitzing observed of the opposite characters of Synedra and SurireUa, 

 that the lateral surfaces exceeded in one the primary surfaces in the other." 

 Several of the species at present placed in this genus may prove, when better 

 known, to belong to Nitzschia. 



* Minute ; attachment slight ; strice 

 indistinct or obsolete. 



Synedra quadrangula (K.). — Very 

 minute, in one view narrowly linear, in 

 the other broad quadrangidar. KB. p. 

 63, t. 3. f. 23. Marine. Norway. 



S.Atomus (K., Nao). — Very minute, in 

 one view elliptic with rounded apices, 

 in the other linear truncate. KSA. p. 

 ^0. = Amphora Atomus, KB. t. 30. f. 70; 

 Synedra minutissima, /3 pelliculosa, K. 

 (according to M. de Brebisson). Fresh 

 water. Europe. 



_ S.perptmlla (K.). — Veryminute; front 

 view very nan-ow linear ; valves lanceo- 

 late, contracted near the obtuse apices. 

 KB. p. 63, t. 3. f. 31. Venice. 



S. Biasolettiana (K.). — Very minute ; 

 front view very narrow linear, arcuate ; 

 valves lanceolate, obtuse. KB. p. 63, t. 

 3. £ 22. Fresh water. Trieste. 



S. pmilla (K.).— Minute ; front view 



broadly linear ; valves oblong-elliptic, 

 with somewhat rounded apices. KB. 

 p. 63, t. 3. f. 29. Carlsbad. 1-1800". 



S. angustata (K.). Front view very 

 narrow linear; valves broader, oblong, 

 with attenuated, rather obtuse apices. 

 1^. p. 64, t. 4. f. 1, 3. Hot springs. 

 Italy. 1-720". ° 



S. virginalis (K.). — Front view linear, 

 truncate, with attenuated centre ; valves 

 lanceolate. KB. p. 64, t. 3. f. 15. Genoa. 

 1-600". 



S. ventricosa (Rab.). — Front view nar- 

 row linear; valves ventricose, with short, 

 produced, beak-like apices. Rab D. p. 52, 

 t. 4. f. 36. Apennines. 



2 * Frustules in lateral view arcuate. 



S. lunaris (E.). — Valves narrow, linear, 

 arcuate, slightly attenuated, obtuse; 

 striae famt, 36 in -001". EI. t. 17 f 4 • 

 SBD. i. p. 69, pi. 11. f. 82. Fresh water! 

 Common. Europe, Asia, and America 

 3e 



