46 MESSES. W. WEST AND G. S. WEST ON 



Long. 517 ih ; lat. ad bas. semicell. 24 /u; ; lat. ad apic. 13'5 ^. 



No. 0. 



The undulations above the larger basal inflation are much less elevated and not so' 

 rounded. Compare with Pleurotcenium truncatulum [=Docidmm truncatulum, W. B, 

 Turn. 1. c. p. 32, tab. iv. fig. 10] and P. haculiforme [^=J)ocidium baculiforme, W. B, 

 Turn. 1. c. p. 33, tab. iv. fig. 15]. 



Genus Closterium, Nitsch. 



22. Clostemtjm lanceolatum, Kiitz. Phycolog. German, p. 30 ; Baifs, Brit. Desm. p. 164,. 

 tab. xxviii. fig. 1). 



Long. 383-175 ^; lat. 55-58 /a. (PI. IX. fig, 21.) 

 No. 5. 



23. Closterium pachtderml^m, nov. sp. (PI. V. fig. 37.) C permagnum, diametro 



circiter 27-plo longius, modice curvatum, subrectum in medio, sensim et gradatim 

 attenuatum apices truncates curvatiores versus ; membrana crassissima, achroa, 

 glabra. 

 Long. 770 /^ ; lat. 28 ii^ ; lat. apic. 8 ^ ; crass, membr. ^. 

 No. 0. 



This species is nearest to C. subangustatum. West (Freshw. Alg. of Maine, Journ. Bot. 

 Dec. 1891, t. 315. figs. 3, 4), in general outline and curvature, but differs in its very thick 

 unstriated and colourless membrane. 



24. Closteritjm Leibleinii, Kiitz. Synops. Diatom, in Linnaea, 1833, p. 596 ; Balfs, 



Brit. Desm. p. 167, tab. xxviii. fig. 4. 

 Forma apice crassior quam forma typica. 

 Lat. 25 /*. (PL V. fig. 38.) 

 No. 0. 



25. Closteritjm Pseudodian^, Boy (Desm. Alford District, in Scott. Nat. Jan. 1890 ; 



icon, in Ut.). 

 Forma brevior et minus attenuata. 

 Long. 100 f/> ; lat. 9 ^. (PI. Y. fig. 39.) 

 No. 0. 



26. Closterium lagoense, Nordst. Desm. Brasil. tab. ii. fig. 2. 



Var. L^VE, nov. var. (PI. IX. fig. 20.) Var. celluhs apices versus paullo crassioribus ; 

 membrana non striata. 

 Lat. 23 fi ; apicibus 116 ^ inter se distantibus. 

 No. 0. 



